I have the 317 casting heads, looks like they are 10.1 head by some other posts with charts. With that, I am going to use the MTI Z1 cam. Should I stick with these heads or go 5.3L heads. I want to run in between 10.5 and 10.725 compression.
What do you think?

 

Your motor's going to be pretty close to mine. I'm building the 408 with Absolute Speed S2 heads and R1 cam. Mines a boost motor though so I'm going for the lower compression. Should come out around 9.0:1 when it's all said and done.

 

With a 4.030 bore, 4.0 stroke, 70cc head, flattop piston with 3 cc worth of valve reliefs, piston .010 in the hole with .050 gasket I came up with about 10.75:1, so stay with the 6.0 heads, the 5.3 heads would need the chambers opened up from the stock 3.80 bore to the 4.030 of the 408. Not to mention the Judson (SAM) CNC program we have on those heads flows around 320-330 @ .600" on the 6.0 heads, which is more then you could ever get out of a 5.3, I put a link below for a compression calculator.

http://www.kb-silvolite.com/temp/calc.php?action=comp