I rebuilt my 2002 700 summit after a total melt down at 600 miles I had to replace both jugs and pistons. I got about 20 mile on the rebuild and it was not running well very bogish. Then engine then stopped I though it had ceased again, but It cooled off and ran again The antifreeze backed up in the resivwere and it was under pressure. I towed it home and put a new head gasket in it again and it ran great for about 5 mile and then did the same thing. Is there a trick that i don't know on getting the head on properly? Could the head be warped?