i'd like to forge my bottom end the engine will get a blower on it and i'd like it to be ready for it so with that being said here are the specs: 347CI (stock crankshaft that'll be turned) and i need it around 9:1 compression, stock rod length. so with 67CC heads would i need a 22cc dished piston? or can someone show me how to do it?

 

http://www.csgnetwork.com/compcalc.html

There's a decent online calculator if you want to mess with it.

 

Assuming...

Cylinder Head Volume (cc) 67
Piston Head Volume (cc) 13
Gasket Thickness (in.) 0.051
Gasket Bore (in.) 3.905
Cylinder Bore Diameter (in.) 3.910
Deck Clearance (in.) -0.005
Stroke (in.) 3.622

STATIC COMPRESSION RATIO
8.986:1

This will greatly change with deck clearance and gasket thickness. Find something close to that or larger and you can change your gasket thickness to accommodate what you find. IE 16cc dish pistons with a 0.035" gasket would put you back at 8.999:1. Just look for something close to 13 with your bore and use one of the calculators in this thread.

There are many good calculators. This is the one I use.

 

thank you guys!

 

Dynamic ratio will most likely be lower if you are running a high(er) duration cam. I don't know how low you are wanting to go on the compression, but that is something to take into consideration.

 

cam will be a 226/232 on a 116LSA lift will be under .600