long version then
you really probably cant do an off the shelf piston, unless you hone or bore the block
but the block needs to be checked out totally by a professional
if you are going to use oem rods, then oem pistons
aftermarket then the block should be measured,
I really cant say it more simply but this is not a small block chevy that anyone can just thro pistons in and hope for the best, I cant count the number of those we have already rebuilt.
so please and no harm intended, but get a builder, contact exotic engines in Arizona, heck jmb performance would not be too far to ship to ,but yank the engine, ship it off and pay the piper.
trust me if you try to do it yourself , you will end up with a piece of glass on top of the block and the rods welded to the bottom of it, sitting in your living room with a glass of tea on top.
not trying to be an ass, but man seriously call Justin, call exotic, pull the pistons out, rods out, send off the block and crank , let them rebuild it, you will be 1000 times happier in the end, just my 2 cents, but have never seen a lot of successful carport builds as yet.
if you insist on doing it yourself, then yes , call Sean, he is an awesome person , and vendor, he will set you up with pistons and rods to work with your engine, I just have a bad feeling you will need some machine work and a little help,
good luck in the new year, let it be prosperous for you