427TTA4

I'm trying to do the correct math here but I'm in need of some expert advice. Stock Ls1 bottom end,stock GM gaskets, milled 317 down .006= 1cc so let's say milled .030= 5cc , 5cc - 71.06 = 66.06 cc size , with a 238/242 .605/.610 112lsa. "ms3 cam". Will milling the 317 that much put me on the red zone or what's the max mill I can go on the stock Ls1 pistons having ptv in mind. I don't mind being in the danger zone, the end I will clay the block to be safe. I got the 317 heads for free so 243s are out the question. Thanks !!