stock bore is 4.250 so +030 would be 4.280 as for rod size you would buy then for a 454 that a 6.135 rod and 4.000 crank that stock for GM 454 .how much CR do you want ? small dome will get you 9.5.1ch or so a flat top would be 8.2.1 this has abit with who makes the pistons