Two books you NEED TO READ: the book by Jim Hand mentioned by Joe in the previous post, and another book by Pete McCarthy. I don't remember the exact title, but it has to do with Pontiac Performance 1955 - 1979. Jim's book is an excellent "how-to" and Pete's book has much specification data.
While there is a LOT of interchangability (it fits); one must be careful that the part that fits will actually work. As an example, Pontiac used head volume to control compression. It is quite possible to change heads and end up with totally unworkable compression ratios.
Jon.
