[Jack21]

$.02 more.

For a street motor the "W" does a great job, and they're plentiful.

The year block you use is more critical to registering your car, and the emissions requirements your State has, than driving it. Catalytic converters weren't installed until the '75 model year. Some States even allow you to register your car as an Antique Vehicle if it's year of registration is 25 years old or older. And most States don't require emissions certification on cars 25 years old. Try to find a pre '75 block. You don't need a Sportsman or SVO block.

What you will likely retain from the original engine will be the block, front timing cover, rods, and crank if you don't stroke it. Everything else pretty much goes in the dumpster.