If you want it bulletproof then you should probably stop buying pre "built" blocks. Get a bare block, take it to a real machine shop that builds race engines and have them measure and buy the correct pistons and machine the block for THOSE pistons, as well as fit the rings properly. I have yet to see any of the prebuilt "built" motors last on big power cars. Whereas the ones I have seen done right, seem to hold up pretty much indefinately. Better bearings, a better oil pump (there are a couple out there) and such. All that should be done.