Open up my 400 B block today...

Oh yea, been to 440source before. Being the comp ratio of the 400 is horribly low, with not much to do with ease to raise the compression up in a meaningful amount, shy of new slugs, there isn’t much to help it.

Swapping to a smaller chamber cylinder head without milling the head can net an approximate 8.5-1. While that is fine for some reasonable street power, I’m not so sure it will like a sizeable cam around 230@050 & up. I’d settle for a 224/226 @050 intake duration and some really good cylinder heads. Though I’d be leaving more than some of the heads power on the table without a good lift to couple with the cam, it would still make a really good easy going driver with good top end.

In my head, I’m working around a 6500 rpm limit.