Pontiac 400 cam ?

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Lemansddj

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Hello I jus got a 73 Pontiac 400 with 4x 7h heads
I was told it has 20k miles on rebuild it looks like it has
Stock pistons but was told the heads were cut to square them up
I purchased an elbrock performer intake and a rebuiltt
800 quad jet carb
What would be a good mild cam to use I want a loopy
Idle
 
a lopey idle is caused by a camshaft with a lot of overlap or one that is tuned for a longer exhaust duration. You cannt throw that type of cam into any engine and expect it to run correctly. If you have a rear end ratio in the 2's, such as a 2.78:1, it will be a dog. Same thing if the compression is too low. Look at the competition cams web site and download their cam selection software or provide more information about your engine and drive train. Automatic or manual, if automatic stock converter or high stall, rear end ratio.
 
It's an auto th350 with stick converter it has a possi with 3:55 gears
 
The 73 400 wasn't a big hp motor so I'm trying to wake it up
I'm replacing my 1970 350 hoping to get more power
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look at the Pontiac 068 type cam which I believe a number of companies reproduce, Crane, maybe Competition Cams, it was used on Ram Air III 400's and 455 HO's.
 
Thanks do you think replacing the 350 with a 400 will get me a big improvement the 350 has a 2bl on it now
 
going from a 2bbl 350 to a 4bbl 400 will make a big difference, with those gears and a 068 or similar cam a very big difference
 
I too am currently building a 400 for my 71 lemans. a lot of people keep recommending summits 2802 cam. i am doing a stroker though so this may not work as well for me. they sound pretty badass on a ram air but they also have high compression and 3.42-3.55 rears for the most part
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yes that cam has some basic requirements

Fair idle, good midrange power. Requires 9.5:1 and higher compression, gearing, and 2,500+ stall. Bracket racing cam.
 
Lemansddj said:
Hello I jus got a 73 Pontiac 400 with 4x 7h heads
I was told it has 20k miles on rebuild it looks like it has
Stock pistons but was told the heads were cut to square them up
I purchased an elbrock performer intake and a rebuiltt
800 quad jet carb
What would be a good mild cam to use I want a loopy
Idle
Click to expand...

The 4x 7h heads are 98cc and with chamfered factory pistons at 15cc this puts CR around 7.6:1. For a low compression 400 take a look at Lunati Voodoo 262\268 fast ramp cam. This cam's lift is walking the line as to what a factory valve train can handle, i.e. need aftermarket valvesprings and screw in rocker studs.

bt
 
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