Ok im ordering pistons but i dont know much about compression ratio and all that so please help..
I have a gsr block
Eagle rods
Blockguard
Headgasket
apr headstuds

turbo running a sc61 using a inline pro manifold,tial wastegate

what piston size should i get to make as much HP as possible

P,s NOT SLEeVING BLOCK!!!

 

stock bore aroudn 9.1 compression should be ideal for you without a sleeved block..

You can go with CP, Wiesco or JE or any brand really.

 

if you're not sleeving your block, then your option is either 81 or 81.5mm
As far as compression, with SC61, I would get 9.5:1 at the lowest and 10:1 will be optimum to me.

stan

 

Dont overbore unless its absolutely necessary. BUT, have the bores checked at a machine shop to see....inspection is more than the naked eye.
Honestly, your question is pretty vague.
But if compression is what your after I would say nothing less than 9:1 and nothing more and 9.8:1
Stay away from JE 81mm 9.8's though.

 

Im sorry for being so vague,,, im looking to stay standard size so i dont have to bore out, i was just looking for best compression to run on the sc61 and have the power and be happy with it...

 

try to stay stock bore at 9:1 to be safe. I personally wouldnt even bother building an unsleeved motor. too many people making good hp on stock bottom end. save your money until you can afford to sleeve it.

 

Thanks motor matrix.... thats what i was thinking about doing..but alot of people tell me too atleast put pistons and rods to be safe.. I had a friend dyno in at 440 on a t3 60-1 turbo last week on a stock block also i was impressed!!!!!