How much can a block be off on this tractor and still get the head gasket to seal. Between one and two cylinders it is low about 3 thousandths of an inch and this is where the head gasket blew last time. We did find that that sleeve was sticking out about 8 thousandths of an inch which would have held the head gasket up on that head design. We filed the sleeves down flush with the block and that is when we found out we were low between those two cylinders. Will this seal now that the sleeves are flush with the block (we are low .003) or is there something to try on that spot. Some say Coppercote but in the past I have not had good luck with that. By the way this is a gas 460. TIA.