Hi,

I'm going to have a 383 short block built for me. The heads I am targeting are the AFR 195 competition port w/ heat riser. Since the engine piston types are variable right now, is there an advantage to having 75cc heads vs 65cc heads, or it normally doesn't matter? I am leaning towards 75cc and using flat top pistons to achieve about 10:1 static compression for use with 91 octane.

The reason I am looking at the heads first is because I need to use the chamber size to determine my piston type (dished or flat). Most everything else on the engine is set.

Thanks!

 

Typically with SBC's, the smaller chamber with dish is the better route. As long as you aren't going domed pistons, though, the larger chambers with flat tops would probably be fine.

 

I've been researching a potential 383 build to the nth degree.
One of the things I've found is that with a 75cc head, flat top pistons with a 5cc valve relief, a .040" piston to head clearence (.015" gasket w/ .025" piston below deck), the most you can get for a static compression ratio is about 9.75:1. Not far off your 10:1 target.
However when considering my anticipated cam duration, I found that under 10:1 wouldn't allow me to reach my intended dynamic compression ratio of 8-8.5:1.
Something to think about when you're picking pistons and cam.