Originally Posted by trigger piston
I got a 300 6 cylinder and Iwant it to scream I was wondering If you could put a 250 crankshaft in a 300 6 cylinder because the 250 got a built proof bottem end. and does any body know about the cut up 351 custom head you can put on it.
Other way around, the 300 has the bullet proof bottom end with a fully counter-weighted forged crank, meatier rods, and thicker block castings. The 240 is a cast crank, light rods and thin wall cast block.
The 302/351 heads are a race only mod. The never solved, seldom mentioned problem is coolant leakage at the join points. While a race engine will stay dry enough for an afternoon, this isn't something you do on a commuter car.