[Safari Larry]

Originally Posted by poison heart

What if I just drill out the holes that should be there? Is this block the same as a '62 389? Are '62 heads better? Are 60 blocks better? Performance wise

There is more to it than drilling the holes in front of the block. You would also need to drill holes in the deck, enlarge holes, and recenter holes. I wouldn't do it -- and didn't do it after careful consideration. I think it could be done.

The 60 block is not the same as '62 389. The interface to the rear of the block was changed in '61 so bell housings will not interchange between 60 and later blocks. Blocks were made a little lighter beginning in '61. If you are building a all out performance engine, the 59/60 block may be better (stronger) than the later block. I believe Steve Barcak uses a 59 block in his dragster.

Performance wise I can't see where there would be any difference between 389 blocks. Later heads will improve performance but I don't know much about that. Valves were made larger and flow characteristics improved over the years as technology evolved. If you want to learn more, there are a couple of good books (1) "Pontiac Musclecar Performance 1955-1979" by Pete McCarthy and (2) "How to Build Max-Performance Pontiac V-8s" by Jim Hand.

If you want to discuss that further, I suggest starting a new thread with an appropriate subject. I think we've gotten a bit off the subject with this thread.