Re: [Amc-list] Crossover or No?

[Frank Swygert <farna@xxxxxxx>]

You lose a little power with the crossover, but it's a negligible amount. It warms the intake floor, which improves economy and reduces emissions. Fuel vaporizes easier and stays suspended better in a warm intake. 

The Edelbrock heads are little more than aluminum copies of the iron heads. There is supposed to be a bit more "meat" in them for porting, but not much. Unless you're planning on running high compression I don't think they're worth the money. So for a street car there's no point in them. You lose a little weight, that's about it. Now if you need a set of heads the Eddy's are the only new heads available, might be better than rebuilding old ones. At least saving the rebuilding time and money cuts the cost some, and you have brand new heads with hardened valve seats. With aluminum you're supposed to be able to run one point more compression than you'd otherwise be able to because aluminum rejects heat faster. 

Since they have to be ported to exceed the performance of iron heads, why not just port the iron heads? If you're planning on this being a street engine that seems to be the way to go, though you could run a little more compression and still easily run pump gas (say run 10:1 instead of 9:1). 

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Date: Fri, 26 Dec 2008 14:12:32 -0500
From: Jim Boone <fljab@xxxxxxxxxxx>

Looking at the Edelbrock catalog & the AMC heads - it lists exhaust crossover port and no crossover port.

Which is best?  Is the no crossover mainly a strip setup, or would that work OK (esp here in FL).

Who does good port work on these?  Anyone you know running them?  Would like to see if they're worth the extra $$ - see dyno results or hear from those that have put them on their cars.

Thinking of the future powerplant & running gear on the American...

-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
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