Re: 440 fuel mileage...
[Re: moparcanuk]
#347053
06/15/09 12:05 PM
06/15/09 12:05 PM
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Joined: Jan 2004
Posts: 9,066 Eugene, Oregon
minivan
OP
master
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OP
master
Joined: Jan 2004
Posts: 9,066
Eugene, Oregon
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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..
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Re: 440 fuel mileage...
[Re: minivan]
#347055
06/15/09 01:09 PM
06/15/09 01:09 PM
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Joined: Jul 2007
Posts: 531 Virginia
JimG
mopar
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mopar
Joined: Jul 2007
Posts: 531
Virginia
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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.
Last edited by JimG; 06/15/09 01:22 PM.
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Re: 440 fuel mileage...
[Re: MNobody]
#347056
06/15/09 01:15 PM
06/15/09 01:15 PM
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Joined: Jan 2003
Posts: 15,551 Norwich CT USA
moparts
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 15,551
Norwich CT USA
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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.
Tom ,
2011 Ram 3500 C&C Diesel 2009 Challenger R/T 1971 Challenger Conv. 511/4 speed 1970 Challenger R/T 503/727
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Re: 440 fuel mileage...
[Re: minivan]
#347058
06/15/09 02:03 PM
06/15/09 02:03 PM
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Joined: Feb 2003
Posts: 21,318 Manitoba, Canada
DaytonaTurbo
Too Many Posts
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Too Many Posts
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
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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.
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Re: 440 fuel mileage...
[Re: Pale_Roader]
#347060
06/15/09 04:16 PM
06/15/09 04:16 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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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?"
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Re: 440 fuel mileage...
#347061
06/15/09 05:23 PM
06/15/09 05:23 PM
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Joined: Oct 2003
Posts: 21,345 Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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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
**Photobucket sucks**
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Re: 440 fuel mileage...
#347063
06/16/09 06:40 AM
06/16/09 06:40 AM
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Joined: Jan 2005
Posts: 4,862 the frozen wastes...
Pale_Roader
Swears too much
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Swears too much
Joined: Jan 2005
Posts: 4,862
the frozen wastes...
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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.
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Re: 440 fuel mileage...
[Re: minivan]
#347064
06/16/09 06:47 AM
06/16/09 06:47 AM
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Joined: Jan 2005
Posts: 4,862 the frozen wastes...
Pale_Roader
Swears too much
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Swears too much
Joined: Jan 2005
Posts: 4,862
the frozen wastes...
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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.
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Re: 440 fuel mileage...
[Re: Pale_Roader]
#347067
06/16/09 11:49 AM
06/16/09 11:49 AM
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Joined: Feb 2003
Posts: 21,318 Manitoba, Canada
DaytonaTurbo
Too Many Posts
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Too Many Posts
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
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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.
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Re: 440 fuel mileage...
[Re: Pale_Roader]
#347069
06/16/09 12:18 PM
06/16/09 12:18 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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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!!!!
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Re: 440 fuel mileage...
[Re: mark7171]
#347071
06/16/09 01:04 PM
06/16/09 01:04 PM
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Joined: Jan 2004
Posts: 9,066 Eugene, Oregon
minivan
OP
master
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OP
master
Joined: Jan 2004
Posts: 9,066
Eugene, Oregon
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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..
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