[sean1969c10]

I think the 307 is a great engine as long as you have reasonable expectation. It's never going to make the power or torque a 350 would, but the bore and stroke sizes are pretty good when you compare it to other engines of similar size. I wouldn't want to try to bore one to 4.00", you would never be able to hone the cylinders straight because there wouldn't be enough cylinder wall left to keep the bore stable. And if you did manage to get the engine together, it would collapse a cylinder very quickly.