One of the few things I ever gave up on was putting an Olds into a 50 GMC. And that was 50 years ago. Its so much easier to start out with a 55-59 that was built to house a V8. Putting a 302 into the earlier ones is so much easier. Putting a big block in one of the earlier ones is doable, but do you have the time? Are you building a race car or a truck to work with?
