Moparts
440 fuel mileage...
Posted By: minivan
440 fuel mileage... - 06/15/09 01:23 AM
So I have run 2 tanks of gas through my 67 stock 375/440 auto... Stock engine, stock cam ,915 heads and the stock AFB that came on the car new.. Everything is rebuilt or new. 294 gears. So far I am getting about 7MPG... Is this normal?? any suggestions as to getting any better MPG.
Posted By: JohnRR
Re: 440 fuel mileage... - 06/15/09 01:33 AM
Leave it parked in the garage ?
what convertor ?
I assume your car didn't come stock with 2.94's ?
But that is a little LOW if you ask me but it is a new engine , extra friction till everything seats .
Posted By: buildanother
Re: 440 fuel mileage... - 06/15/09 01:38 AM
Highway mpg better get over 10 easily, or somethings wrong.
Posted By: SomeCarGuy
Re: 440 fuel mileage... - 06/15/09 01:39 AM
What is the timing set at? Initial and total
Did you degree the cam in?
Brakes dragging?
The 7 MPG is very low IMO
Posted By: minivan
Re: 440 fuel mileage... - 06/15/09 01:45 AM
Car came with 3.23 gears
Initial timing 7BTDC
cam was not degreed
Drum brakes adjusted loose..
I was hoping for 10-12....
Posted By: SomeCarGuy
Re: 440 fuel mileage... - 06/15/09 01:48 AM
Try bumping to 12 BTDC.
Are you certain the TDC mark is correct?
10-12 is not hard for a stock setup.
What convertor are you running? Maybe it is too loose for the 2.94 gear.
Posted By: Jerry
Re: 440 fuel mileage... - 06/15/09 03:03 AM
is the vacuum advance hooked up? how much compression? do you have quench? is the carb jetted correctly? do you have a wideband o2 sensor?
Posted By: landon1
Re: 440 fuel mileage... - 06/15/09 03:06 AM
my 440 was well-worn, but with the WAY too small 600 Holley that was on it, i got about 7 or 8 in town and 10 on the highway....switched to a 650 DP Holley and get about 13...i was hoping with the rebuild, i'd get much better...still hoping, despite your troubles...i'm interested in hearing more
Posted By: DaytonaTurbo
Re: 440 fuel mileage... - 06/15/09 03:31 AM
Not sure what my mpg is, but I've got a tired smogger 440 with a thermoquad and I daily drive it everywhere and it's very reasonable on fuel for what it is. I don't complain about its mileage. How heavy is your right foot? I drive mine pretty casually most of the time and mileage is acceptable.
Posted By: landon1
Re: 440 fuel mileage... - 06/15/09 03:33 AM
Quote:
Not sure what my mpg is, but I've got a tired smogger 440 with a thermoquad and I daily drive it everywhere and it's very reasonable on fuel for what it is. I don't complain about its mileage. How heavy is your right foot? I drive mine pretty casually most of the time and mileage is acceptable.
pretty heavy foot somedays 
Posted By: dOc !
Re: 440 fuel mileage... - 06/15/09 03:46 AM
In my 62 Belvedere .... stock and worn-out 440 with a 509 cam.... TQ with a SD intake and iron exh mans and a 2.76 gear ... got 17 mpg ....
....and ran bottom 12's ...at 100 mph or so.(BAD speed for that ET because of poor ring seal).
Something REALLY is wrong with your FRESH combo. I would check the primary jetting on that carb. It has to be way WAY fat.
Suggestions? .... a Plastic Fantastic ...aka ThermoQuad.
Posted By: dave571
Re: 440 fuel mileage... - 06/15/09 04:28 AM
still a stock cam in there?
I think I would look at the distributor. could have seized weights. Should do better than that with that combo.
I bet I got close to 20 mpCDNg in my stock cammed 383 2bbl 68 newport.(16 mpusg or so)
I would think 12-15 would be a reasonable expectation if the foot is lightened
Posted By: Dusted_Ya
Re: 440 fuel mileage... - 06/15/09 04:44 AM
78 Powerwagon with 32" mud tires, 4:10 gears and I'm getting 8.5mpg on the highway. Either you are not getting any timing advance or your carb is somehow causing a very rich environment. Pull a couple of plugs and smell them/inspect for rich condition
Posted By: Robbins
Re: 440 fuel mileage... - 06/15/09 04:59 AM
My buddy's 74 factor 440 truck with 3.55's, 3/4 ton gets 14 on the highway. Unloaded........of course.
Posted By: minivan
Re: 440 fuel mileage... - 06/15/09 05:31 AM
Brand new plug an play pertronix distributor.. I have not checked it for total advance yet.. The original, rebuilt, AFB is on the car. I forget its number but it is correct for a 67 auto 375/440.. I want to assume its jetted as it was from the factory.. I think the car is rich and will check jetting and timing..
Wanted to have car running by May 30th, so I need to go back and fine tune somethings.. My question was "is this kinda crummy MPG" for a 440...
Posted By: minivan
Re: 440 fuel mileage... - 06/15/09 05:34 AM
Yes vacuum advance to the port on the carb.
low stall torque converter..
9.2-9.3 compression..
915 heads..
Well rick, I have an Aussie Charger with a stroker 440(500 ci)with comp cams 294 solid(248@050)Wiend Xcelerator single-plane,Stealth Heads,650 D/Pumper Holley(YES,650)10:1 comp 193 lbs cranking pressure,factory dizzy set at 36 degrees total with 22 initial advance.MSD 6AL ignition.
I run a 4-speed new-process with 2:75 gears out back with 25 inch diameter wheels.
This car weighs over 4100 lbs with me & fuel & it runs 12:00 @ 118 mph & does 17 mpg Imperial which I guess is about 15 US to the gallon.
Now I use all the throttle when I accelerate wherever I can & cruise about 70-90 mph.
Would suggest you get your total timing right & then get your initial set after that. Not hard to do.
If thats alright get into that damn carbby; something is very wrong.
cheers, Mike.
Posted By: Pale_Roader
Re: 440 fuel mileage... - 06/15/09 08:56 AM
Personally, i think 440's just suck in this dept. compared to other makes. I haven't owned them all, but i've had a few 440's, some were nice runners, good tune and car etc. They all got [Edited by Moparts - Keep it clean] mileage. My Charger with its stock 76 440, full (very nice) exhaust, elect. ign, de-optioned (as in no power anything) and no air cleaner even gets around 8MPG. Thats with 3.23 gears and i know how to drive for mileage.
I've never had a 440 in anything that could touch my 68 Cadillac's mileage, and thats a high-comp 472 in a 6000lb car with all kinds ov problems.
I blame the lack ov quench more than anything. My Caddy has it, my Charger (and other Mopars) never had it. Mopars just aren't efficient from the factory in my opinion. You need to rebuild them and buy some real pistons.
Posted By: Pale_Roader
Re: 440 fuel mileage... - 06/15/09 09:13 AM
Ideas for better mileage? First and foremost, hows your driving? I know everyone is the best driver in the world, but the difference between two different drivers in mileage can be vast. Lets assume you know how to squeeze the most from a tank.
Exhaust, probably the biggest improvement i've seen (other than fixing something that wasn't working right) was with exhaust. Headers, 2 1/2" (MINIMUM) or 3" mandrel pipe, X-pipe, high flow mufflers. Theres a LOT there over a stock style system.
Distributor recurve, putting a good tune into the distributor is a nice improvement over the stock tune.
Friction in the driveline, vibrations cost power/mileage, as do improperly inflated tires.
Hotter/better spark, MSD ignition? I haven't done this yet, but from all accounts, this is a nice improvement over stock as well.
Intake, maybe a weird suggestion, but everything improved when i put a Street Dominator on my 440. Went up eight jet sizes and still ended up with better mileage. That stock intake really does suck.
Better carb? Again, i dont know about this first hand (i always use Holleys) but everyone tells me that Thermoquad is magic... IF it works the way its supposed to. I DO know that a Q-jet is superior to a Holley, so i would think a plastic Thermo would be as good or better?
Use the LOWEST stall converter you can get away with....???
Put a serious shift kit in the tranny.
Synthetic fluids from front to back. You'll be out over $100, but this made a seat-o-the-pants difference in my 96 Mustang GT, and those cars already get wicked mileage.
And my personal favorite (after the exhaust)... weight reduction. Put 'er on a diet.
Posted By: JimG
Re: 440 fuel mileage... - 06/15/09 12:15 PM
My sig car was bone stock except for MP electronic ignition when I bought it in 1981, and it got waaaaay better than 10 on the highway, around 14+. I drove it to Myrtle Beach from Virginia in 1982 and I remember it wasn't terrible.
My compression ratio was advertised as being higher that yours, although I didn't measure how far down the pistons were in the hole when I built the motor the first time in 1984. Ah, the indescretions of youth!
You've got some good suggestions so far. I assume you have a stock cam since you're running the stock AFB? Those carbs were calibrated very well for the stock engine, and should give razor-sharp performance and decent mileage if everything is as it should be. You might want to get an O2 bung welded into your exhaust somewhere and pay someone with a wideband meter to give it a look-see to be sure the factory calibration is still intact. Someone may have changed jets, metering rods, springs, etc. I still have my original AFB disassembled in a box - if necessary I can tell you which rods and jets it has. Springs might be more difficult to identify.
With a dialback timing light or with a timing tape installed, be sure the advance curve looks good, and be sure the vacuum advance is working right. The spring tension on the vacuum advance is adjustable if you're running a stock distributor or the MP unit - if you don't know how to adjust it one of us will explain it if you're interested.
Posted By: moparcanuk
Re: 440 fuel mileage... - 06/15/09 02:57 PM
Stock 440, clean air filter, electronic ignition, proper tire pressure, 3:23 gears and 94 Octane gets me 15-16mpg (Imperial gallons) @60mph highway.
Oh yea, and a light foot on those on ramps.
Posted By: minivan
Re: 440 fuel mileage... - 06/15/09 04:05 PM
I guess I should add more here..
The engine ( and car) were rebuilt from the ground up. 67 coronet R/T vert. original engine and torque flite..
Engine was bored 40 over, forged pistons with a compression ratio of 9.2-9.3 to 1 after ccin the 915 heads.. Machine shop had the cam ( with about 1 inch of dust on the box) that was for a 375 horse 440.. Original carb 4327S, I think thats the number, rebuilt.. Stock original HP exhaust manifolds with a new accurate exhaust system including the "hi flow" hemi mufflers. I have just been cruising the car with only a couple of "breakin" heavy throttle passes. My stock points distributor was worn out so I installed, straight out of the box, a Pertronix billet plug and play distributor, and timed it to 7 bftdc pulling the vac advance line while timing.
Engine has a slight hesitation to it when I throttle it quickly and has backfired a few times when doing this.. I question my ability to rebuild the carb and I think the carb is pretty worn out.. I was going to install a new edelbrock but wanted to give the stock carb a try.. Was told it smelled very rich at warm start up by some friends...
Would a small vacuum leak contribute to poor mileage?? Thanks for all the help.. Oh and here is a pic of my 18 year project..
Posted By: MNobody
Re: 440 fuel mileage... - 06/15/09 04:42 PM
Sounds like you need to do some carb tuning, check for vacuum leaks with some carb cleaner around the carb and vacuum lines. my 318 only get's 10mpg....
Posted By: JimG
Re: 440 fuel mileage... - 06/15/09 05:09 PM
Nice car! I wish my car had an up-down switch on the dash!
I would try getting the stock carb working before going aftermarket. That carb was calibrated to your engine by Chrysler engineers who spent hundreds of hours getting it right. Since you have a stock engine, if you can reclaim the original calibration, you'll be head and shoulders above taking a universal carb out of a box, bolting it on, and expecting it to be matched to your engine.
If you'd rather check what you've got before spending the money, you can have someone check the air-fuel ratio with a wideband meter. It's possible to check it at the tailpipe (so you don't have to install a bung) but it's not quite as accurate. Still better than nothing, though.
Since you seem unsure of your ability, carb wise, I'd recommend talking to good carb shops (some of whom are Moparts members) about refurbishing your carb and (here's the important part) maintaining the as-delivered calibration.
Otherwise, be sure your vacuum advance is working (as others have said) and if it's tunable, be sure it's coming in soon. You should have 38 degrees total advance by 2500 RPM or so with the vacuum advance disconnected.
Did I mention that I REALLY like your car?
Jim
ETA: I checked my original carb, and mine is a 4326S - I would guess that I'm one number off from yours due to the fact that mine is a 4-speed. Mine has 350 and 498 jets. The metering rods don't have numbers that my 49-year-old eyes can read, but I'll be happy to check them with a micrometer and let you know the measurements. The metering rod springs - I have no idea how to identify the ones in my carb.
If you're concerned that someone has changed parts in your carb, using the same calibraration as mine would get you darn close.
Shout back if I can give you any more info.
Posted By: moparts
Re: 440 fuel mileage... - 06/15/09 05:15 PM
Just for comparison, my 511 big block, .600 lift cam, 830 Holly DP gets 10 mpg over all. With 35 degrees of total timing with a very fast advance, all in at idle.
What I would do is re curve the dist for a faster advance, Set a total advance of around 35 degrees revved up.
This will give you around 15 degrees at idle. This is what the stock MP dist start with. If you don't have any pinging with this, then try adding the vacuum advance also for cruise speeds.
Posted By: minivan
Re: 440 fuel mileage... - 06/15/09 05:41 PM
Thanks to all for the compliments and suggestions.. I will focus on the timing, carb and look for any vacuum leaks, although it idles well..
I pulled the car out of a field in 90, the plates have 82 stickers on them, and the first time I have driven it was 2 weeks ago.. Other than the fuel mileage its alot of fun.. I can actually watch my fuel gauge move...
Another pic.
Posted By: DaytonaTurbo
Re: 440 fuel mileage... - 06/15/09 06:03 PM
Quote:
Engine has a slight hesitation to it when I throttle it quickly and has backfired a few times when doing this..
Not enough initial ignition timing. I would try curving the distributor to run 15* initial and 35 total w/o vacuum advance. Then after the motor is running well at that level hook up the vac advance. You may have to play with the vac advance adjustment a bit because it may give too much vac advance at first causing you to ping during cruise or light accel. Some combos will tolerate a lot of vac advance, others will not.
Posted By: minivan
Re: 440 fuel mileage... - 06/15/09 06:07 PM
Thanks Daytona.. I just haven't had the time to fool with it.. There is absolutely NO pinging as is, so I wanna think I can get more advance out of it no problem...
Posted By: Anonymous
Re: 440 fuel mileage... - 06/15/09 08:16 PM
Quote:
...i think 4...40's just suck in this dept. ....... stock 76 440, ..... gets around 8MPG.
I've never had a 440 in anything that could touch my 68 Cadillac's mileage,
Well let's put things in perspective, shall we? In 76, all makes had about the worst engine combo's going, thanks to Federal and CA smog laws, so you are comparing your 76 smogger to your 68 Caddie?
Here's a better example: Back in the day, my 70 sixpack RR--with OUT the sixpack, got 13.8 at 70mpg, and I DO NOT drive "for mileage." When I wanted to "leave" I "left" When I wanted to pass a car, they knew they'd been passed. When I used to get on a freeway, there was no doubt that "we" were going to merge. This was with an Edelbrock and 800DP.
The combo was: stock 440sixpack engine, headers, stock mufflers, Dana 3.54, G60 tires, and 3000 RPM at 70 mph. The car had "hang on AC" and an air grabber, not that it matters. That car with that combo would run 13.0's all night long at Carlsbad. I could not afford two rear axles, so 3.54's is what I ran
So the point is this: 13.8mpg, no careful driving, a car that would leave a 68 Caddie so far behind you couldn't see it after a couple of minutes, and much cooler to be seen in. As Dr Schill would say "are YOU KIDDIN ME?"
Posted By: 70Cuda383
Re: 440 fuel mileage... - 06/15/09 09:23 PM
I just put mine through a 200 mile trip this weekend up to B/E&A for the get together. my 438 (383 .060 over, with a 440 crank...all BUT a 440!) with a .525 lift cam, edelbrock RPM heads, 750 holley HP, and dyno'd at 535 tq @ 3600 rpm and 505 hp @ 5800 rpm...got 10 mpg on the trip.
and that's in a 4200 lbs truck with the aerodynamics of a brick...sideways!
gears are a TKO-600 with .64OD, rear axle is a 4.56 ratio and 29" tires...I was turning 2650 RPM at 75mph. it'll do the speed limit at 2400 RPM
Posted By: SomeCarGuy
Re: 440 fuel mileage... - 06/16/09 05:05 AM
Your carb either has problems or it may in fact be too lean. That can cause a backfire like that. Being too lean can cause you to use more fuel as well, even though that is counterintuitive.
If you do decdie to get a new carb, DO NOT get a 1407 or 1411 Eddy.
The other Eddy carbs should be fine, with the AVS versions being the front runners. You can rebuild the carb yourself with not much trouble. THe exploed view should be all you need. Most have a sheet showing how to measure a few things like float drop.
Posted By: Pale_Roader
Re: 440 fuel mileage... - 06/16/09 10:40 AM
Quote:
Well let's put things in perspective, shall we? In 76, all makes had about the worst engine combo's going, thanks to Federal and CA smog laws, so you are comparing your 76 smogger to your 68 Caddie?
When you get right down to it, a 76 is no different than a 72, heads, CR, slightly better in some areas, slightly worse in others. Both are about as inefficient as a big-block came. I should add that my 76 is essentially running 72 parts, intake, MP dist., the carb and exhaust are aftermarket, its been effectively de-smogged, etc. It has a six pack cam as well and was well tuned. So yeah, i'm comparing my nicely installed "76" to a 68 Cad 472 with a lot ov problems... in a car that is 1400lbs heavier with a windshield you could show drive-in movies on.
Quote:
Here's a better example: Back in the day, my 70 sixpack RR--with OUT the sixpack, got 13.8 at 70mpg, and I DO NOT drive "for mileage." When I wanted to "leave" I "left" When I wanted to pass a car, they knew they'd been passed. When I used to get on a freeway, there was no doubt that "we" were going to merge. This was with an Edelbrock and 800DP.
Haha, nice.
Quote:
The combo was: stock 440sixpack engine, headers, stock mufflers, Dana 3.54, G60 tires, and 3000 RPM at 70 mph. The car had "hang on AC" and an air grabber, not that it matters. That car with that combo would run 13.0's all night long at Carlsbad. I could not afford two rear axles, so 3.54's is what I ran
So the point is this: 13.8mpg, no careful driving, a car that would leave a 68 Caddie so far behind you couldn't see it after a couple of minutes,
Yes, i'm sure you would leave my SIX THOUSAND POUND Caddy behind. That really doesn't take much doing. So will my Charger on its worst day. Someday i will go crazy with the weight-reduction on it and get that beast down to a svelte 5200lbs... then i'll be beating up on 300's and Imperials ALL day long. Hahahahaha
Quote:
and much cooler to be seen in.
Uh... NO. The debate rages, but i doubt it.
Posted By: Pale_Roader
Re: 440 fuel mileage... - 06/16/09 10:47 AM
Quote:
I guess I should add more here..
Stock original HP exhaust manifolds with a new accurate exhaust system including the "hi flow" hemi mufflers.
That is exactly what i was talking about concerning restrictive exhaust systems. Thats about enough pipe and muffler for a 318 4bbl. If you're not attached to the stock look and sound and are still looking for some more efficiency later on, look into a TTI X-pipe system and headers for a 440 in your car. Its really a win win deal. More power, better efficiency, cool sound.
Posted By: terzmo
Re: 440 fuel mileage... - 06/16/09 02:30 PM
I have a 950 procomp on a 498 stroker with 355's and around town I get over 10 UNLESS I jump on it and then the gas gauge goes into cardiac arrest....
Posted By: SomeCarGuy
Re: 440 fuel mileage... - 06/16/09 03:00 PM
The exhaust he has is fine for his app.
No way it is causing that low of a MPG.
Posted By: DaytonaTurbo
Re: 440 fuel mileage... - 06/16/09 03:49 PM
Quote:
Quote:
Well let's put things in perspective, shall we? In 76, all makes had about the worst engine combo's going, thanks to Federal and CA smog laws, so you are comparing your 76 smogger to your 68 Caddie?
When you get right down to it, a 76 is no different than a 72, heads, CR, slightly better in some areas, slightly worse in others. Both are about as inefficient as a big-block came. I should add that my 76 is essentially running 72 parts, intake, MP dist., the carb and exhaust are aftermarket, its been effectively de-smogged, etc. It has a six pack cam as well and was well tuned. So yeah, i'm comparing my nicely installed "76" to a 68 Cad 472 with a lot ov problems... in a car that is 1400lbs heavier with a windshield you could show drive-in movies on.
Good job ignoring the fact that your 76 440 has a whopping 7.5:1 of factory compression ratio. Compression = efficiency and anything out of the late 60's would have had a CR in the 9's most likely. Then you take a smogger 440 and add a bit of cam to it, well you didn't have much cylinder pressure to start with any any cam over a stock passenger car/lo-po cam will drag down mpg.
Quote:
The exhaust he has is fine for his app.
No way it is causing that low of a MPG.
Big block cars with granny gears in the rear could click off better mileage than that from the factory, and the factory gave you a worse exhaust than what you've got on there now.
Also everyone thinks their car is well-tuned until someone puts a wideband o2 on it. Not to mention making sure the distributor is curved properly, a smogger 440 won't want the same curve as a 10:1 440.
Posted By: YYZ
Re: 440 fuel mileage... - 06/16/09 04:03 PM
Seems low.
In my last Challenger it would pull an easy 17+ mpg (US Gal) in town or on the highway and it wasn't fully broken in.
Rebuilt 71 440-6 with 10:1 compression
Comp Cams XE262 (not enough cam IMHO)
Factory 6 pack intake w/stock Holleys
3.23 SG axle
4-speed
Electronic ignition - I forget what I set the vacuum advance at, but as much as it would stand.
Carbs were pretty lean. Per the other guy's post, they were even worse for economy with the 'as delivered' jets & power valve and the car ran too hot. Fattening up the mixture helped.
If you got into it, yes you could see the fuel gauge move, but with normal driving it was quite decent on gas.
Posted By: Anonymous
Re: 440 fuel mileage... - 06/16/09 04:18 PM
Quote:
leave my SIX THOUSAND POUND Caddy svelte 5200lbs... then i'll be beating up on 300's and Imperials ALL day long. Hahahahaha
First of all, your (I'll refrain from added descriptors I'd love to add) Caddy doesn't weigh any 6000 lbs unless it's a hearse, and if it does weigh that much, two things:
you've got way too much bondo and lead aboard
and you're just plain lying about mileage figures
So I'll give you a BETTER example.
Years ago a friend and I fixed up THIS combo:
74 Dodge 4x4, yanked the 360 2bbl and installed a 440, essentially the combo would be equiv to stock 440 magnum. It would STILL kick your Caddy's ass, and got nearly 14 with the gearing in the p.u. in 2x4 and hubs kicked out
NOW THAT THING WEIGHED 6000 lbs!!!!
Posted By: mark7171
Re: 440 fuel mileage... - 06/16/09 04:20 PM
323" A body 4dr with 4 spd no O/D 3.23 gears= 14-16 mpg.
440" E body w/ 4 spd N/OD and 3.23 gears= 10-11mpg.
All well tuned street drivers. Using an 1 to 4 skip shift provies the best results for me.
Posted By: minivan
Re: 440 fuel mileage... - 06/16/09 05:04 PM
Again thanks to all for the comments on here. I am aware that I need to dial in a few things, just appreciate any ideas or thoughts..
I had an A12 super bee in High School ( 1973), so I remember bad mileage, but it was a 410 rear car also..
My current car was pulled out of a field in 1990.. The car was complete but needed a complete resto. The previous owners son told me it used to "pass everything on the road but the gas station"..
I am pretty sure with some carb and distributor work I can at least get 10-12 out of it...
I will disagree with the exhaust comments on here though.. I am 54 and I had plenty of cars "in the day" that had headers on them.. NEVER again on a street car.
A story.... In about 73, three of us were working on our "fast" cars.. I can't remember if were installing plugs, tuning carbs, or what, but were dirty, greasy, hot and tired... It was a saturday and we were getting ready for cruising and hot babes that night.. A friend ( who had some of the hottest cars I have ever been in) pulled up in a 65 corvette convertible he had just purchased.. 327, powerglide car.. I looked at him and said " what you going to do with that?"... He just smiled, while looking at the good looking brunette next to him, and said " were going to the beach".... think about it..
Posted By: bordin34
Re: 440 fuel mileage... - 06/16/09 09:32 PM
My 73 400 gets absolutely terrible mileage. In my 73 Charger with 2.45 rear gears i get around 6mpg if I am lucky and driving normally. The only problem I have is the previous owner cross-threaded one jet in the primary metering block, could that be my problem?
Posted By: SomeCarGuy
Re: 440 fuel mileage... - 06/17/09 04:21 AM
If you are getting only 6, it could have multiple problems. We need details to be able to tell you much. What have you checked or changed?
Posted By: Pale_Roader
Re: 440 fuel mileage... - 06/17/09 11:09 AM
Quote:
First of all, your (I'll refrain from added descriptors I'd love to add) Caddy doesn't weigh any 6000 lbs unless it's a hearse
Well you nailed it. 68 M&M hearse to be exact, and i know exactly how much my car weighs. Its no lightweight. Had it down to just 5500 once with the interior gutted to sheetmetal and the bench seat.
Quote:
74 Dodge 4x4, yanked the 360 2bbl and installed a 440, essentially the combo would be equiv to stock 440 magnum. It would STILL kick your Caddy's ass, and got nearly 14 with the gearing in the p.u. in 2x4 and hubs kicked out
I'll take that race. I said it was slower than the Charger, but its pretty damn fast for three tons and highway gears. I'd put it up against any stockish 6000lb rig that isn't a diesel. I bet your trucks got a lot better gearing than my deathmobile.
I know we're not allowed to admit other makes are fast on Moparts, but i think the guys on a Caddy forum would take issue with your comment. Caddy's are kinda like Buicks... the math is just different.
All in good fun, huh...???
Posted By: Pale_Roader
Re: 440 fuel mileage... - 06/17/09 11:23 AM
Quote:
Good job ignoring the fact that your 76 440 has a whopping 7.5:1 of factory compression ratio. Compression = efficiency and anything out of the late 60's would have had a CR in the 9's most likely. Then you take a smogger 440 and add a bit of cam to it, well you didn't have much cylinder pressure to start with any any cam over a stock passenger car/lo-po cam will drag down mpg.
Not ignoring anything here. I know this thing aint the best factory design (kinda my point), but the OP's car aint pushing much past 9 either. The engine i ran before this one was a 67, with the stock "10:1" and it was a pig too. It wasn't as nice an engine as the current one, but the CR made up for it. Both got about the same mileage in this car. I guess what i'm saying is that the OP has a factory set-up, which is hardly what i'd consider an efficient engine design (sorry Mopar gods...). If you were to go through the trouble to install a 500 Caddy behind the 727 in the same car (uh oh... blasphemy!) just to prove a point, i guarantee you'd see a dramatic improvement in MPG and power... despite the obvious cid increase.
Quote:
The exhaust he has is fine for his app.
I disagree.
Quote:
No way it is causing that low of a MPG.
I agree. I didn't say it was CAUSING the problem. He asked what he could do to improve MPG. Replacing it with an optimized system certainly would.
Posted By: SomeCarGuy
Re: 440 fuel mileage... - 06/17/09 01:42 PM
The mufflers he has on there flow plenty, the bends should be mandrel with that system, and have a H pipe. That is plenty enough, and not a hinderance to MPG.
Posted By: bobby66
Re: 440 fuel mileage... - 06/17/09 02:07 PM
When you check the timing, are you disconnecting the vacuum advance? More initial would help, with total between 34-38.
Posted By: Mr.Yuck
Re: 440 fuel mileage... - 06/17/09 08:55 PM
who cares...why did you use a 440 if you want mpg's? the 2 don't mix. That said you should be doing better than 7mpg. I had a S/C'd 440 coronet w/ 3.91's and managed 11-12mpg at 70-75 mph
Posted By: Anonymous
Re: 440 fuel mileage... - 06/17/09 09:25 PM
Honestly it should be about double what you're getting if that's highway miles.
Posted By: Bill MeLater
Re: 440 fuel mileage... - 06/17/09 09:34 PM
Quote:
who cares...why did you use a 440 if you want mpg's? the 2 don't mix. That said you should be doing better than 7mpg. I had a S/C'd 440 coronet w/ 3.91's and managed 11-12mpg at 70-75 mph
EXACTLY: Figure around $30.00 a day for a reasonable ride at todays gas prices. The alternative is my '96 Dakota 2.5....I try to use that only for work. Enjoy...
Posted By: DaytonaTurbo
Re: 440 fuel mileage... - 06/17/09 09:59 PM
Reminds me of the 20 mpg 440 thread from a couple years ago...
https://board.moparts.org/ubbthreads/show...rt=all&vc=1
Posted By: SomeCarGuy
Re: 440 fuel mileage... - 06/18/09 01:04 AM
You guys that "don't care", don't drive much.
If he gets the MPG up to at least 12, he almost cuts his fuel bill in half, leaving more money for extra drives or improving the car in some way, or you name it.
Posted By: minivan
Re: 440 fuel mileage... - 06/18/09 03:37 AM
Quote:
You guys that "don't care", don't drive much.
If he gets the MPG up to at least 12, he almost cuts his fuel bill in half, leaving more money for extra drives or improving the car in some way, or you name it.
Now were talking..
Posted By: dOc !
Re: 440 fuel mileage... - 06/18/09 03:43 AM
GOOD ring-seal ... reasonable rpms ...and a nice safe lean air/fuel mixture = very decent MPG.
Posted By: SomeCarGuy
Re: 440 fuel mileage... - 06/18/09 03:55 AM
Have you checked anything else yet?
That cam not being degreed in is a real problem IMO. You can spend a ton of time chasing things and never find anything wrong.
Posted By: minivan
Re: 440 fuel mileage... - 06/18/09 04:02 AM
I have the cap and rotor out of the distributor and was goin to install the light springs and a bit stumped on the mechanical advance limiters supplied with the pertronix dist. ( see my other thread).. Was/am going to take it to my mechanic guru friday..
Made a score today at the Junkyard for the correct AFB carb base for my dual snorkel air cleaner. Was using an AVS base with an adapter.. keeping the AVS base "just in case"...
So by not degreeing the cam and just setting it to the timing chain marks means that cam timing can be off?? thanks
Posted By: Lefty
Re: 440 fuel mileage... - 06/18/09 05:03 AM
Check the timing. My 440 picked up power and economy when I bought a new Pertronix plug and play dist. I checked the curve with a dial back timing light and it matched the recommended curve in this Mopar Action tech question. I think adding the vacuum advance helped the fuel economy the most.
http://www.moparaction.com/Tech/quest/SLOW_CURVE.html
Posted By: Lefty
Re: 440 fuel mileage... - 06/18/09 05:06 AM
Quote:
( see my other thread)
I just realized I replied the same in the other thread, didn't know it was you with two similar questions... 
Posted By: SomeCarGuy
Re: 440 fuel mileage... - 06/18/09 05:38 AM
It isn't likely to be off w/o a degree job, but you wouldn't be the first or even one of a few that has had a cam that was off enough to cost a lot of power. Of course if that is the case PG cn suffer...
I wouldn't sweat the degree deal at this point, it just makes this that much harder to figure out. That is why I always post to do the check while it is apart. Rules that out right off the bat.
The timing tab not being dead on with the balancer mark could have you off from what you are seeing on the light as well.