I went with 4.360 bore for a few reasons, mainly because if had I a failure, I may be able to just bore cylinders out and keep on going without having to replace sleeves. I took this approach on my Mega block and was able to bore from 4.350 to 4.440 when I broke a rod and then 4.440 to 4.50 when I dropped a valve. I also had a really nice set of Diamond pistons that were 4.360 that I was planning to use but when I decided to move to B1s, I had to buy new pistons. I asked Scott Koffel about the bore and he said it would be fine. I'm don't need 1,000hp so not trying to get every HP out of it. (I had Ken Black put the 4.5" darton sleeves in the block so they are just super super thick as they weren't the normal 4.5" sleeve they typically use.)

Yes, this is going in my 1971 Barracuda

Question for you guys, will I be able to use my header that I've been running with Indy -1s? (they are 2 1/4 so plenty big enough, just wasn't sure if they exhaust ports moved up or down from the -1s)