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My 440 is a slug, please help.
#471559
09/18/09 09:27 AM
09/18/09 09:27 AM
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Joined: Nov 2003
Posts: 154
Gator73
OP
member
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OP
member
Joined: Nov 2003
Posts: 154
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Like the title says, my 71 440 runs like a slug and has very little low end torque. It doesn't even want to spin the tires with 3:55 gears. We have a few theories on why it may be lazy but wanted to check here for some additional ideas. Here is the background on the engine. This was a bone stock 71 440 that has been in my 74 Roadrunner for years. It ran great when the engine was put in the car but over the years, the stock AVS would dead spot and no amount of tuning or rebuilding would fix it. Since there were some other small issues to address on the engine, we decided to remove it and replace the cam, timing, chain, carb and intake. Used a Crower 267HDP (220 and 223 @50 with 478 and 486 lift 112 lobe separation angle). On went a Holley Street Dominator and a new Edelbrock 800 Thunder Series AVS. It should be noted that we are using stock 73 HP Magnum exhaust manifolds. The car starts, idles,and runs nice and doesn't even really have any lope at all from the cam. The timing is set at 11 initial and doesn't ping. It bogs a lot when you step on it from a stop. Air door has already been adjusted some but hasn't cured the problem. So, anybody got any ideas? Is the Street Dominator killing off the bottom end in this combination despite the fact that it is generally known as a good low-end intake? I think the AVS carb should run pretty good on a stock-type engine and not be too much. The cam is also pretty mild and should not make a dog out of it. We have a Weiand Action Plus we can try to see if that brings back some of the low end but it is so dead I don't know what will help. A 440 like this should melt the tires. Any help would be greatly appreciated.
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Re: My 440 is a slug, please help.
[Re: Joshs68]
#471567
09/18/09 10:30 AM
09/18/09 10:30 AM
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Joined: Jan 2003
Posts: 5,443
Indiana
YO7_A66
master
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master
Joined: Jan 2003
Posts: 5,443
Indiana
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I agree with Josh. Initial timing is very important in a street car with a larger than stock cam and an auto.
You wrote that you have 11 degrees initial timing, now once you know what your in gear (foot on brake, engine at running temp) vacuum reading is, you have a base line.
Then I would suggest bumping the initial timing up to 15-18 degrees (since you have a larger than stock cam) and retune your in-gear vacuum to the highest number at the same rpm as you had with the 11 degrees. If your vacuum reading went up, then the motor wanted it. Then you would want to recurve your distributor for your total timing and then test drive the car. If you gained in gear vacuum, then you will gain bottom end response too if the carb is tuned correctly. That 800 Edy should be fine for your setup. Get the timing correct first and then finish tuning the carb.
1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)
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Re: My 440 is a slug, please help.
[Re: Gator73]
#471568
09/18/09 10:35 AM
09/18/09 10:35 AM
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Joined: Jan 2007
Posts: 780
Woodinville, WA
Viol8r
super stock
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super stock
Joined: Jan 2007
Posts: 780
Woodinville, WA
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Quote:
Yeah, I wouldn't think the SD would be causing the problem given the rave reviews it gets. Maybe it just works better on hotter engines rather than my relatively stock combo. Anybody ever use a SD on a stockish engine and have low end issues? I agree that changing carbs to a known good one regardless of the brand could elimiate a lot of guess work. I'll have to beat the bushes to see if I can scare a good candidate up.
You will lose a little bit of bottom end with the SD vs. the RPM (or dual plane). A few things jump out at me. Not enough compression, no stall, not enough initial timing, and the wrong carb.
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Re: My 440 is a slug, please help.
[Re: Viol8r]
#471569
09/18/09 10:47 AM
09/18/09 10:47 AM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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fix the timing and the bog in the carb. EDIT all oe AVS's are emissions era carbs & you might get an eddie strip kit & some flat metering rod caps & richen it.
Last edited by RapidRobert; 09/18/09 10:51 AM.
live every 24 hour block of time like it's your last day on earth
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Re: My 440 is a slug, please help.
[Re: terzmo]
#471574
09/18/09 12:37 PM
09/18/09 12:37 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
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Posts: 16,123
Grand Haven, MI
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what kind of vaccuum are you pulling at idle?
did you do a compression test?
if you have a lot of vacuum at idle (13+" In gear), changing the stock orange step up springs (5" vaccuum) to the pink or natural (7 or 8") will help a lot with a lean bog at tip in.
also, there's 3 holes on the acc pump lever to adjust the volume of the pump shot, closer to the carb the hole is, the bigger the shot. play around with that adjustment as well.
do you have any vacuum leaks?
if your compression test shows low, did you degree in the cam? If it's installed slightly retarded (say, 112 ICL instead of 108) the later intake closing point will cause the cranking compression will drop, and low RPM torque will be reduced.
Last edited by patrick; 09/18/09 12:40 PM.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: My 440 is a slug, please help.
[Re: Gator73]
#471577
09/18/09 03:18 PM
09/18/09 03:18 PM
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Joined: Jan 2007
Posts: 780
Woodinville, WA
Viol8r
super stock
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super stock
Joined: Jan 2007
Posts: 780
Woodinville, WA
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This combo is just not a barn burner, sorry my friend. An 8.5:1 iron headed, stock bottom, no stall 440 is just not going to feel real quick. Especially with a single plane intake and too much carb.
There is good chance those pistons are way down in the whole with a early 70's block. I am guessing 6.5:1 dynamic compression.
I would cut .040" off the heads, get a dual plane, go to a 750 Holley, headers, that will wake her up.
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Re: My 440 is a slug, please help.
[Re: Gator73]
#471580
09/18/09 04:43 PM
09/18/09 04:43 PM
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Joined: Feb 2005
Posts: 5,221
Branson, Mo.
joedust451
super gas
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super gas
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
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Quote:
This is a higher mileage engine and the compression was checked before going into this. The cylinder pressure varied amongst the cylinders and ranged from a high of 145 to a low of 130. I thought I posted about these numbers and whether they would be ok, but I can't seem to find the post. Anyway, from what I gathered on other similar posts, my compression while not great was not all that bad. I believed the engine to be in good enough condition that it could take a mild cam along with the new timing chain, intake, and carb. All advice on timing including vacuum readings will be considered and we'll see how much additional it can take. I believe the pump shot is still in the stock position and we can play with that some too after the timing is figured out. It doesn't have any off idle stumble under moderate throttle or anything like that, just bogs when you try to open it up. This car runs great and could be driven all day long but just simply has no guts.
Those #s are a bit low, not horrible, but on the lower end, most stock 440s will be around 150-155, don't know what to tell ya other then you may want to check it agian, they may be alot lower, but like said, it might be carb/timing related.
Last edited by joedust451; 09/18/09 04:45 PM.
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Re: My 440 is a slug, please help.
[Re: Gator73]
#471581
09/18/09 04:46 PM
09/18/09 04:46 PM
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Joined: Nov 2006
Posts: 2,255
IL
furious70
top fuel
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top fuel
Joined: Nov 2006
Posts: 2,255
IL
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Quote:
Yeah, I wouldn't think the SD would be causing the problem given the rave reviews it gets. Maybe it just works better on hotter engines rather than my relatively stock combo. Anybody ever use a SD on a stockish engine and have low end issues? I agree that changing carbs to a known good one regardless of the brand could elimiate a lot of guess work. I'll have to beat the bushes to see if I can scare a good candidate up.
Not a 440, but a 383.
~8:1, 268H cam, basically a stock rebuild smog engine with headers and a holley 750dp
4000lbs Fury, 275/60/15's
SD intake and 3.91's from an idle would barely chirp the tires
stock iron 4bbl intake and 3.23's from an idle I'd get a little spin
To be fair, I did not try to optimize timing for each intake, but for the gear change in the opposite direction I thought it a pretty substantial loss in tq with the holley intake. The big 383 intake comparo HotRod did confirms this. How that translates to a 440 is a bit up in the air however.
Last edited by furious70; 09/18/09 04:47 PM.
70 Sport Fury
68 Charger
69 Coronet
72 RR
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Re: My 440 is a slug, please help.
[Re: Gator73]
#471585
09/19/09 10:53 AM
09/19/09 10:53 AM
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Joined: Jan 2003
Posts: 74,978
U.S.S.A.
JohnRR
I Win
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I Win
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Quote:
John, the distributor is a stock Mopar replacement unit from a parts store that was bought years ago (not a Mopar Performance unit). It was recurved some time ago and has one heavy spring and one light spring. It seems to be working find. I have thought about replacing it with a known good MP unit to see if that would help.
was it recurved by just changing springs ? if so you probably have too much total timing since std mopar distributors have 30 plus degrees of mechanical advance , changing the springs does nothing to change that . But that's not your problem here .
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Re: My 440 is a slug, please help.
[Re: JohnRR]
#471587
09/19/09 01:57 PM
09/19/09 01:57 PM
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Joined: Jan 2003
Posts: 25,200
Upper Midwest
MoparforLife
Too Many Posts
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Too Many Posts
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Upper Midwest
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Quote:
That cam isn't very big , looks like a modern version of the stock 440 magnum cam .
John - That cam in a small block is a great runner. Lots of low end torque and retains a good amount of vacuun. IMO it should run good in a 440 as well. 
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Re: My 440 is a slug, please help.
[Re: MoparforLife]
#471588
09/19/09 02:44 PM
09/19/09 02:44 PM
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Joined: Jan 2003
Posts: 74,978
U.S.S.A.
JohnRR
I Win
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I Win
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U.S.S.A.
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Quote:
Quote:
That cam isn't very big , looks like a modern version of the stock 440 magnum cam .
John - That cam in a small block is a great runner. Lots of low end torque and retains a good amount of vacuun. IMO it should run good in a 440 as well.
Don , I never said anything about how it would run , my comment was just saying that is not as big a cam as some seem to think .
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Re: My 440 is a slug, please help.
[Re: Gator73]
#471589
09/19/09 05:21 PM
09/19/09 05:21 PM
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Joined: Nov 2004
Posts: 2,825
Sk. Canada
RemCharger
master
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master
Joined: Nov 2004
Posts: 2,825
Sk. Canada
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Quote:
John, don't know what other modifications the guy did other than putting in the springs and I never inquired as to how much timing it had. The car ran great after the initial engine swap and had plenty of power (about 15 years ago).
There is an update to this story. From what I can remember, my friend told me he unhooked the vacuum advance and gave it more timing. It took it all the way up to about 21 initial and 38 total. Made a big difference in power as it will spin the tires. The Street Dominator is coming off and will be replaced by the Weiand Action Plus. I am running a stock air cleaner and it nearly hits the hood with the SD. Can't run a spacer with the SD which we need due to heat soak. I expect the change in intake will make a big difference in the low end and we'll adjust the timing again after the switch. The SD just doesn't appear to be a good match for this combo. I'll give an update with specifics after this is completed. Thanks to all who have posted with advice thus far.
I would time it first, before the swap... With that cam it should like that intake IMO. I've run similar combos, and thats what i've found.
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Re: My 440 is a slug, please help.
[Re: JohnRR]
#471590
09/19/09 08:23 PM
09/19/09 08:23 PM
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Joined: Jan 2003
Posts: 25,200
Upper Midwest
MoparforLife
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,200
Upper Midwest
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Quote:
Quote:
Quote:
That cam isn't very big , looks like a modern version of the stock 440 magnum cam .
John - That cam in a small block is a great runner. Lots of low end torque and retains a good amount of vacuun. IMO it should run good in a 440 as well.
Don , I never said anything about how it would run , my comment was just saying that is not as big a cam as some seem to think .
Right it is not a real big cam but it seemed to have a lot of low and midrange when I had it in the Duster and it works great on the street in the Coronet 360. The engine has stock dished pistons too. Like you said it is not huge but a good torky cam.
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Re: My 440 is a slug, please help.
[Re: Gator73]
#471592
09/20/09 01:34 AM
09/20/09 01:34 AM
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Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo
Too Many Posts
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Too Many Posts
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Posts: 21,318
Manitoba, Canada
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Holley SD is not a good choice for that combo. Holley SD likes more timing than a dual plane even on a combo it's suited for, which is one with torq to spare. Quote:
I do understand that all carbs may need tuning to get optimal performance but I would think the Thunder Series AVS would run pretty good right out of the box.
You can never assume that. I have a wideband o2 on my car, and trust me, baselined or out of the box tuning can be miles off. For example baselined to stock specifications I was getting a 17:1 a/f at a hot idle as well as cruise and a bad bog at WOT with my thermoquad. Not the same as an eddy thunder but mine's a 440 pre-smog era thermoquad an on the new combo it was crazy far off from ideal.
I've got a low-cr smog 440 stock bottom end w/ new piston rings, lunati voodoo 60303(226/234@050, 494/512 lift, 110lsa) cam, 440source heads, headers and a stock spreadbore intake w/ thermoquad. I was going to do a full rebuild but didn't have the money and decided to throw something together to have fun with instead of sitting on these parts until the end of time. It fries tires great off the line, the back end goes all over the place. Great street manners and I still drive the car to work and will do so until the snow flies.
FWIW my cylinder compression ##'s were a bit better than yours, even with the bigger cam.
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Re: My 440 is a slug, please help.
[Re: Joshs68]
#471599
09/20/09 06:11 PM
09/20/09 06:11 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
Initial timing is very important! ask a carb shop if you want a second opinion. What is the total timing? I would give it more initial. try for 15-18* initial with a total of 35-37* should be plenty.
EXACTLY.......Don't ever listen to ANYONE that tells you otherwise.........Just as you discovered, initial timing is EXTREMELY important.........You might read this THREAD to better understand ........
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