I am curious as to what the optimal piston to wall clearance should be with forged pistons due to the expansion when they heat up. I am in the process of putting my engine together and want to do everything right. I will be using JE pistons.

 

You can check out Endyn's site for some typical clearances with forged pistons:
http://www.theoldone.com/articles/en...ata_sheet.html

 

that was some great info but are you sure that is for forged pistons. They seem a little on the tight side.

 

How much boost? talked to a tech at JE. I told him my piston spec, how much boost and he said 4thou. He said upto around 20psi.....3-3.5thou....and after 20psi = 4thou.

 

I am planning to run around 15-16 psi on the turbo and then a little NOS with it (maybe like a 75 shot). i have to calll them but from the looks of it I think that the 4 thousandths would be the way to go.