Thread: Finally Building the 350 this week... what do you think about the setup?

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Originally Posted by Henry Rifle

That's the 305 Magnum. Comp Cams says: Pro Street/Bracket, limited street driving, 3,500+ stall, racy idle, 10.5:1 CR. If you run less than 3,500 stall, you've got problems. Also, your compression ration is likely too high for pump gas.

I wouldn't judge these heads strictly on the intake port volume. This is the head that GMPP puts on the ZZ-4 block to produce the "Fast Burn 385" motor, and that the dealers like Sallee Chevrolet use on their "ZZ-383." In both of those engines, they get about 9.7:1 compression with a flat-top piston. (I'm not saying that these are the same flat top piston in 67's engine.) All I'm saying is that with the right piston and cam, these heads work really well on a SBC.

With all that said, it's still too much cam and too much compression for the street. Eric's recommendation for about 15 degrees less duration on both sides is in the ballpark, and makes the cam very similar to Chevy's LT4 "Hot Cam." Get the compression down to about 10:1 and use about 2400 stall. Seriously, you will not like that cam on the street. I like the heads, though.

When I made the post about the heads I did not go into great detail about them.
They have a large port volume but they are not very efficient.
A good street head would be the AFR 180 cc street head.The AFR head is 30 cc's smaller and will out flow the other heads from .100 lift to .600 lift.In fact in the mid-lift area .300 lift the Chevy head flows 173 the AFR flows 195 cfm.
On the exhaust side the Chevy head flows 120 cfm at .300 lift.
The AFR flows 156 cfm at .300 lift on the exhaust side.
The whole idea is to have a smaller cross section and great flowing port.
Before anyone say's the Gm head is less money which is true.From what I can tell there is around $100 difference in cost.
Which head would you rather have?