440 build Advice needed
#3108776
01/05/23 06:52 AM
01/05/23 06:52 AM
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Joined: Jun 2018
Posts: 118 Oklahoma City, Oklahoma
MrMayhem
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Good morning gentlemen,
I currently have a 440 sitting on the dyno with somewhat disappointing results. I pieced together a combo that I had hoped to make north of 550hp but am falling about 30HP short of that. The first thing that has me somewhat confused is that the motor is only pulling 680 cfm through the carb. I would have expected at least an additional 100 cfm. The torque curve is good and amazlingly flat from 3000 rpm up to 5000-ish making at or above 500lbft through much of the curve. The motor peak hp at 5600 rpm ended up at 519hp and fell fairly quickly after that. By 6000 rpm the motor was done making power. The builder says I need more cam (duration), I think he is wrong and something else is choking the motor. I have posted the 1st dyno run numbers which was a short pull but is consistant with the following pulls up to 6k. 32 degrees of timing on pump 91 octane gas. What do you guys think?
Here are the motor Specs:
Stock stroke 440. Cast crank & LY rods ICON 968 .030 pistions. Zero Deck height Compression is just a smidge over 11.1:1 with .039 gasket Toth Ported ProMaxx heads (300+on flow bench) cfm on intake Finished Chamber is 76cc PAC Springs and Comp retainers/locks Hughes engines Solid Cam STL5054BS3-8 BB SLD FLAT TAPPET CAM 250/254 -108ºLSA 3 BOLT .392"/.400" LOBE LIFT: Gross Lift I .627/E .640 with 1.6 Rocker Hughes Roller Rocker 1.6 ratio Trick Flow single pane intake, port matched. MSD Dist/Ignition Set at 32 degrees at full advance. Melling HV oil pump and Milodon pan.
Last edited by MrMayhem; 01/05/23 06:54 AM.
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Re: 440 build Advice needed
[Re: MrMayhem]
#3108777
01/05/23 06:59 AM
01/05/23 06:59 AM
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Joined: Sep 2012
Posts: 40 West Central Indiana
PROSTOCKTOM
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In my opinion you have the wrong intake on that combination. Switch to a Performer RPM and you should see better results.
Tom
Molnar Technologies Full Service Dealer - Crankshafts & Connecting Rods
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Re: 440 build Advice needed
[Re: MrMayhem]
#3108788
01/05/23 08:22 AM
01/05/23 08:22 AM
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Joined: Nov 2011
Posts: 291 PA
Harry's Taxi 2
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I think your builder is correct. You need more duration......and ignition timing.
'86 Maple Grove KOS Mopar low qualifier......true street legal with no power adders.
NOS-used when losing since 1940.
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Re: 440 build Advice needed
[Re: fbs63]
#3108832
01/05/23 10:13 AM
01/05/23 10:13 AM
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Joined: Jun 2018
Posts: 118 Oklahoma City, Oklahoma
MrMayhem
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What did the heads flow @.600 lift? Did you try more timing? You know what cranking compression is? Seems to me it could use more timing. I'd have to go back and review the numbers but the flow numbers in the low 300's if I recall correctly... I dont know the cranking pressure offhand but the timing was limted to 32 degrees due to detination
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Re: 440 build Advice needed
[Re: jwb123]
#3108837
01/05/23 10:21 AM
01/05/23 10:21 AM
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Joined: Jun 2018
Posts: 118 Oklahoma City, Oklahoma
MrMayhem
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Just to throw it out there, I agree would have tried more timing. The BSFC numbers look poor, it is using a lot of fuel to make the power, but the A/F ratio is close. Did you degree the camshaft? First thing I would do is get a cranking compression reading, might tell you if cam is not right. The builder did degree the cam, I can confirm that. Not sure what cranking pressure is, I'll refer the builder for the information
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Re: 440 build Advice needed
[Re: MrMayhem]
#3108838
01/05/23 10:24 AM
01/05/23 10:24 AM
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Joined: May 2014
Posts: 179 California, U.S.A.
Torquemonster440
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The Vac Secondary carb isn't helping. Recent episode of Engine Masters showed a significant increase in peak hp and tq with a double pumper on the dyno vs the same sized vac Secondary carbs. Logic being that as RPM increases the vacuum through the Secondary venturis pull additional fuel through the squirter nozzles of the dp carb. They have video confirming the phenomenon. Something like 15 hp if memory serves me. If you can source an 850 holley dp, give that a shot. More timing like others have suggested could help also. A larger double Pumper carb and timing sweeps are easy to do in comparison to a cam swap.Good luck.
1966 Satellie.. 12.55 @107.75. 906 heads. 3780 lbs.
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Re: 440 build Advice needed
[Re: Torquemonster440]
#3108847
01/05/23 10:38 AM
01/05/23 10:38 AM
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Joined: Jun 2018
Posts: 118 Oklahoma City, Oklahoma
MrMayhem
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The Vac Secondary carb isn't helping. Recent episode of Engine Masters showed a significant increase in peak hp and tq with a double pumper on the dyno vs the same sized vac Secondary carbs. Logic being that as RPM increases the vacuum through the Secondary venturis pull additional fuel through the squirter nozzles of the dp carb. They have video confirming the phenomenon. Something like 15 hp if memory serves me. If you can source an 850 holley dp, give that a shot. More timing like others have suggested could help also. A larger double Pumper carb and timing sweeps are easy to do in comparison to a cam swap.Good luck. I believe the last dyno pull was with a Holley 950HP carb
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Re: 440 build Advice needed
[Re: MrMayhem]
#3108849
01/05/23 10:44 AM
01/05/23 10:44 AM
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Joined: Jan 2003
Posts: 13,492 Marion, South Carolina [><]
an8sec70cuda
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Add some race fuel and bump up the timing. Otherwise, I'd be looking at a cam change if you want to stick w/ pump gas.
CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 4 speed, Dana 60 '71 Demon 340, no drivetrain, on blocks behind the barn '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax
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Re: 440 build Advice needed
[Re: jwb123]
#3108859
01/05/23 11:05 AM
01/05/23 11:05 AM
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Joined: Jun 2018
Posts: 118 Oklahoma City, Oklahoma
MrMayhem
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Just to throw it out there, I agree would have tried more timing. The BSFC numbers look poor, it is using a lot of fuel to make the power, but the A/F ratio is close. Did you degree the camshaft? First thing I would do is get a cranking compression reading, might tell you if cam is not right. Cranking pressue was-190psi... 251 intake duration 256 exhaust 108 lobe separation: 78 degrees of split overlap per the builder So if I were to look at a cam swap, what would be the reconmendation?
Last edited by MrMayhem; 01/05/23 11:08 AM.
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Re: 440 build Advice needed
[Re: jwb123]
#3108864
01/05/23 11:18 AM
01/05/23 11:18 AM
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Joined: Feb 2008
Posts: 724 Central TEXAS!!!!
sr4440
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Just to throw it out there, I agree would have tried more timing. The BSFC numbers look poor, it is using a lot of fuel to make the power, but the A/F ratio is close. Did you degree the camshaft? First thing I would do is get a cranking compression reading, might tell you if cam is not right. jwb123 is correct, the VE numbers are off, looks like about 8%. That being said, it's using a good about of air and using a LOT of fuel to make power. The A/F numbers are not that accurate because of the way they are calculated, i would prefer O2 sensors. So my question, did you pull any jet out of it, and how did it respond? Joe
Without Data, you’re just another guy with an opinion.
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Re: 440 build Advice needed
[Re: sasquatch]
#3108879
01/05/23 11:54 AM
01/05/23 11:54 AM
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Joined: Jun 2018
Posts: 118 Oklahoma City, Oklahoma
MrMayhem
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Like Chip said.....Put some good fuel in it and bump the timing to about 36 and your power will appear like magic. 11 to 1 compression on pump 91 fuel is going to get you in trouble most of the time with a wedge engine. If you cannot run more than 32 degrees without detonation you have to much compression for the fuel you are using. Todd I stand corrected: Builder says it made no difference in HP or Torque by moving timing up to 36 then back to 32. Lost power under 32 degrees
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Re: 440 build Advice needed
[Re: an8sec70cuda]
#3108882
01/05/23 11:56 AM
01/05/23 11:56 AM
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Joined: Jun 2018
Posts: 118 Oklahoma City, Oklahoma
MrMayhem
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Add some race fuel and bump up the timing. Otherwise, I'd be looking at a cam change if you want to stick w/ pump gas. Do you have a reconmendation on which direction to go with the cam?
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Re: 440 build Advice needed
[Re: MrMayhem]
#3108883
01/05/23 12:00 PM
01/05/23 12:00 PM
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Joined: Jan 2003
Posts: 13,492 Marion, South Carolina [><]
an8sec70cuda
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Add some race fuel and bump up the timing. Otherwise, I'd be looking at a cam change if you want to stick w/ pump gas. Do you have a reconmendation on which direction to go with the cam? Fast68plymouth here on the board is the cam guru. Porter Racing Heads 802-951-1955
CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 4 speed, Dana 60 '71 Demon 340, no drivetrain, on blocks behind the barn '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax
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Re: 440 build Advice needed
[Re: AndyF]
#3108914
01/05/23 12:57 PM
01/05/23 12:57 PM
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Joined: Jan 2003
Posts: 14,531 So. Burlington, Vt.
fast68plymouth
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Unfortunately, without some history from that dyno, or results from other similar builds....... you’re just “racing dynos”.
The FW headers aren’t helping with the top end power.
Cam is not too big(motor makes decent TQ).
VE numbers are in la-la land(imo, they’re just plain wrong).
Bsfc numbers are poor.
But, that’s two examples of why you’d need to have history with that dyno to really assess the results.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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