Quote:

Hypothetical Q: If a person replaced a set of 452's w a set of eddies and the chamber/port dimentions were IDENTICAL on each (1) what would be the difference in performance (if any) and (2) With the aluminum conducting heat faster would that be what would be making this difference (if there's a difference)? and (3) if the eng (w the 452's) was at the ping limit with his current choice of fuel (and his current CR) if the SCR was was raised (w NO other changes) would he be able to run the same octane w no pinging? and (4) if so would there be a gain in power (w the higher CR/alum heads (which'd be wicking away heat)?



The following are just my somewhat educated opinions. I am not a professional engine builder, just a hobbyist. with that said, I'll take a swing at these Q's:

1) IF everything else was the identical, and only the material was in question: none, if anything the iron heads might offer a very slight horsepower advantage, but aluminum weighs less, so your car gets lighter. Advantage Aluminum.

2) The difference would be that just as aluminum dicipates the heat, it also dicipates energy (this is why its good when used at main caps). Since it dicipates energy at a slightly higher rate than iron, the iron heads would create more energy inside the cylinder, hence, slightly more HP. (emphasis on SLIGHTLY)

3) depends on how much you raise the compression. because of the same pricipals noted @ #2, you can use slightly more static compression with aluminum. with that said, If I was the OP, I'd opt for the Eddy large chamber heads to break even, or slightly lower my compression (11:1 is too much for pump gas in my book, even with aluminum heads)

4)more compression generally = more power. but again, at 11:1 on pump gas, I would'nt look to raise it.

Hope that helps, let me know if you dissagree.

LemonWedge - Street heavy / Strip ready - 11.07 @ 120