But if you are changing the pistons even on a brand new engine you need to rebore it as all 4 pistons are not the same size even from standard.

 

you may find my build page handy, I'm running a very similar setup to you minus the tvs.

http://www.ionforums.com/forums/perf...lding-lsj.html

enjoy and good luck
ps. lots of pics

 

thats not realy true considering the pistons now are cnc machined and not hand machined what needs to be done is the bore checked to make sure it is still within spec then check the piston to cylnder clearance

ill tell you the problem ive been runnnign into even on a low milage engines is shity finish machine work from gm on the bores

 

There are actually 3 sizes of stock pistons, they select the size of piston which is the best fit for the bore and stamp the block to say which size should go in there.

 

well i havent found any stampings on the blocks i have as of yet and if that is the case just have the bores miced and order custom piston diameter

 

yup i found it but how do you decipher it

 

I'm not sure, I was just told by someone who knew the build process well, that that was the way it's done.

When I asked whether I could swap the pistons straight over as it was a new engine and the bores should be all the same I was told I could not do it for this reason.

 

well you can get the bores checked and get a custom oversize