I'm pretty sure the head bolts are 1/2", but I'm also pretty sure the engine-to-tranny bolts are 3/8" for the 250 and 235. I've actually not worked on a 216, guess I'm assuming they're the same... smile

-Boyo


'48 Willys CJ-2A / '55.1 Chevy 3600 / '66 Austin-Healey 3000 / '04 Volvo wagon (parenthood!?)