235s are a dime a dozen. Just check Ebay. They usually go for about 100 if you can pick one up locally. Rebuilding them to stock specs isn't too expensive if you have a complete motor. Warming them up is a different story. The 848 head is more desirable AND the correct head for the year. It offers higher compression hence more power. A 250 or 292 will require some fabrication for the mounts at least.
