Steve - I think the C. I. likes to move around a bit after some heating/cooling cycles. Thats why we have to 'line bore' the mains on blocks. Sometimes even the cam bores need line boring. If you just put a good machinists straight edge across a lot of our blocks you'll see the trouble. Running a indicator over them on a mill table is a better way. Exhaust man. crack, same deal. Some years of motors are notorious for that until the factories correct their castings. Thats why industrial inlines are commonly made w/one head for 2 (only) cylinders. Doug
