Stroking the crankshaft to your most 81mm will keep the RPM capacity intact. Bores may be brought out to 83mm, but try out to keep it beneath 82.5mm. There is not any require for the Method Atlantic crankshaft. Reject blocks that can need to have 83mm to wash up, obviously There may be head problems also.The 5 valve head is Toyota's bonus to the 4A