The 307 was a "compromise" engine that Chevy built in the late '60s. It had the bore of a 283 with the stroke of a 327. The idea was to keep the smaller bore for fuel economy, but increase the stroke slightly for more torque. The engine was intended for the heavier vehicles like Impalas and light-duty trucks, but GM used them in everything from Camaros to maxi-vans.

The majority of them came with small valve heads (1.75 / 1.50) and 2-barrel carb, but they can be made to run pretty good for the street. They're a pretty tough engine, too.

I took a '67 Impala with a 307 into a demo-derby many years ago. I lost the radiator early on, but kept running anyway. That little 307 never missed a beat in an event that went on seemingly forever. I ended up 2nd after the winner finally put me out by crunching the right front fender in until the inner apron sheared off the fuel pump. When I climbed out of the car, the exhaust manifolds were glowing red! A friend of mine took the engine, cleaned & painted it, changed the cam, installed a 4-barrel intake & carb, and bolted it in his T-bucket. It absolutely screamed.

For a hundred bucks, buy it. If nothing else, you can put the crank in a 350 block and have a large journal 327.