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Discussion Starter #1
I have a sbc 406 ci, currently have an Iron Pro Topline, 50 cc chamber, Flat top SRP 2 relief pistons. With this setup i have approx 13.4:1 comp.

I am looking into getting an AFR 245 or 235 head. With one of these heads i will have a 70cc chamber on the 245, and a 65cc on the 235. Dropping my comp ratio to 10.5:1 - 11:1.

Will the decrease in comp ratio & increase in air flow work out right to gain some good hp. If i could run 10.5:1 and run pump gas, that would be great!
 

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Those are large heads for a 406 cid!! You're gonna need turn a lot of RPM to get these heads to work with your engine size. your final result will depend of your current head and what was done to them if any. It may very well happen also that the cam will not work with the new heads. Since you are in the Detroit area why not look into the DART heads??
 

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Dart 215 platinums would be a better choice IMO.
 

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Discussion Starter #10
yes why would afr require piston change? and not a dart or air wolf? all 64, 65cc chambers
 

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btw mr 82bird you will need more duration. if ya want it to work right... that big of head on 406 will need more rpm. id say make your power around 8000. unless you go more cubes..:)
 

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Discussion Starter #15
current heads flow 282 I , 195 E. Switching to a shaft rocker wouldnt be a problem, but would rather stay with my current ones. Was looking into AFR because of the cost compared to their flow numbers
 

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i though all standard sbc had a 60/40 valve spacing?.... hmmmmmmmm...
60/40 means moved .060/.040 FROM standard valve location.

I don't know that he'd need new pistons but perhaps just flycutting the ones he has would do. Only mocking it up would tell for sure.
 

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Both AFR's are 60/40 spacing which is not GM standard and also require rocker shaft per AFR. This is a good example that just going by the flow numbers is the wrong thing to do. You would be better of with a smaller heads (than the AFR) custom ported for your application. Or you will have to spin this thing above 8000rpm to make it happy.
 

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Discussion Starter #19
thanks for all the info everyone, this is exactly why I posted first! So what should be the max runner volume i should be looking at for my cubic inch, or basically the best head for my application
 
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