Re: My engine sucks
[Re: ireland383]
#953011
03/18/11 09:29 AM
03/18/11 09:29 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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Dont have actual #'s to offer but bottom line does it have a flat spot and on the other end you dont want it open at a higher in hg than needed. EDIT yes the 1/2 rule is good but when the vac levels are low enough on a particular build it can change that general rule
Last edited by RapidRobert; 03/18/11 09:31 AM.
live every 24 hour block of time like it's your last day on earth
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Re: My engine sucks
[Re: Kern Dog]
#953014
03/18/11 10:49 AM
03/18/11 10:49 AM
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Joined: May 2003
Posts: 6,569 Downtown Roebuck Ont
Twostick
Still wishing...
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Still wishing...
Joined: May 2003
Posts: 6,569
Downtown Roebuck Ont
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Quote:
I was tuning the 440/493 in the Charger and part of this includes checking idle vacuum to determine the proper size Power Valve for the Speed Demon 850 carburetor. I already have a 3.5 PV in the carb now. The motor is a '74 440 with a 4.15 stroke crank, 10.8 to one squeeze, Edelbrock heads and RPM intake. 2" TTI headers and the '509 Mopar cam. Holleys website suggests to take a reading of the idle vacuum while IN GEAR and install a power valve with a number that is HALF of the vacuum. When I checked mine, I got a number of 7 inches of vacuum! Granted the engine wasnt fully warmed up. I pulled the choke plate some time ago since the car will idle dead cold even when its 40 degrees outside. It does idle better once it is warmed up, but my question is....... Whats your combo and idle vacuum numbers? I never checked this on other cars before, so I dont know what to think. I'm going to take another reading with the motor at operating temperature and I'm guessing that it will be a higher number than 7 inches. If not, I guess the PV is right as is.
My combo is almost identical to yours only 8.97:1 and EFI. Same cam too if yours is the 108 lsa. Mine IIRC pulls about 8-9" in gear at 900-1000 rpm. I run 18 deg initial timing and I run a 2800 T/A converter. That cam has 76 deg of overlap so it's not big on vacuum.
If the weather stays nice today I'm going to bring it out of hibernation and I can verify my sketchy memory .
Kevin
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Post deleted by moparts
[Re: bigblock340power]
#953018
03/20/11 04:26 AM
03/20/11 04:26 AM
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Anonymous
Unregistered
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Anonymous
Unregistered
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