I am making some changes with the motor in my boat. I have the "D" shaped exhaust ports on the new heads. The question that I have is, can you grind the ports on the manifolds to match. There appears to be enough material.......

FYI, it is a small block.

One other question........ How much horsepower can these manifolds/dry pipes support. 450,500,550..........?

Thanks in advance!

I heard of a guy that had a procharged 434 cu. SB pushing somewhere around 700 or so HP through stainless marine manifolds and long risrs so 550 will be fine I would think.

Thanks for the input! Motor came off of the dyno at 594 HP @ 6200. I have dry tails so I guess I will see how it performs with them!