Got a Cam question

[THE STIG]

So I've been stock piling parts for my 75 440. The motor is mostly stock except for the Edelbrock 650 cfm on top. I've got a set of rebuilt 452 heads with 1.81 Intake valve, 2.14 exhaust, Stainless steel valves, comp cams valves, locks,retainers,new guides, 88cc combustion chambers, .600 lift springs Ithink that's all. So now I'm looking at an Edelbrock Performer or RPM intake but I'm not sure the RPM will fit under the hood of my Charger since it's a high rise and all. And then comes the Cam, an Edelbrock rep told me to run the 2192 http://www.edelbrock.com/automotive_new/mc/camshafts/cams_chrysler_bb.shtml
So what are your thoughts on all this? Is there a Mopar Purple cam that's better?

 

[WileE]

That manifold fits under the hood of a road runner, if that helps. I've used the mopar cams over the years, but I'd recommend a more modern profile. I got one from Hughes & it outperformed the 509 cam, with better driveability.

 

[Meep-Meep]

What is your compression? If you are running the original 75 440 pistons you don't have much to work with. The cam listed will most likely be fine if you have low compression but get a confirmation from Edelbrock.

 

[THE STIG]

That manifold fits under the hood of a road runner, if that helps. I've used the mopar cams over the years, but I'd recommend a more modern profile. I got one from Hughes & it outperformed the 509 cam, with better driveability.

The RPM fits or just the standard Performer?

 

[THE STIG]

What is your compression? If you are running the original 75 440 pistons you don't have much to work with. The cam listed will most likely be fine if you have low compression but get a confirmation from Edelbrock.

I have no clue what the compression is but was told that in stock form the engine was like 8.5:1 or somthing like that, at least that's what the Edelbrock guy told me and he said it would run fine just make it more "efficent". And what will my compression ratio be after I replace the heads and intake? As for the pistons I'm assuming they are stock but I'm not certain, but I have had my eye on a new set of Keith Black's.

 

[Meep-Meep]

I agree with the Eddy guy on the CR estimate. Too much cam and you will kill it - as in performance. Your compression ratio will not change if you rebuild the same heads and put them back on with the same thickness gasket. If you have a burned valve then that cyl/cyls will have increased compression pressure but not ratio. The intake has no influence on CR or cyl pressure; only efficiency in a particular RPM range. Higher compression even with the cam listed would be an upgrade in performance.

 

[Cranky]

Cams measured at .050 lift is the way you want to know what they are doing and that cam will created a lot of cylinder pressure in the lower rpm range and plenty of vacuum. It's what many refer to as an 'RV' cam. Makes power from the drop of the hat. Says not for 68 and earlier...I wouldn't use it with compression in the 9-1 range either unless you like pinging. Your engine might ping with it too if the temps are high enough since a 75 block has pistons way down in the bore so there's no quench and the design of the old heads don't lend themselves to stopping a second flame front from occurring very well....

 

[WileE]

The RPM fits or just the standard Performer?

Sorry... it was the RPM

 

[THE STIG]

What if I ran a .0020 shim gasket would that improve my CR? Thanks for all the input BTW, I bow to all of you and your vastly superior knowledge. I work with a dude who has an 06 Mustang and it's the fastest car in Indiana if you don't believe me just ask him he'll tell ya, and my objective is to hand him his *** this summer.

 

[Meep-Meep]

Going with the steel shim gasket (.020" not .0020") will increase compression by a few tenths of a point and adding closed chamber heads, if you had them, usually increases CR by nearly half a point. Having only 8-8.5:1 CR to work with is a big limitation to making power unless you're putting a turbo on it. Hmmmm, now there's an idea!