Buddy of mine is finishing up his engine builds.

509CI
Blower spec cams
Merlin Iron heads with mild port work
8-71 Mooneyham blowers with superchillers

Currently he has the standard stainless marine manifolds, with long dry tails. His builder suggested going to a header, like CMI or stelling. I had always thought that in a application like this, with the blowers turning say 7psi, he can still make good power with the stainless marine manifolds. The question is, how much if any would he be leaving on the table, compared to say a CMI tube header?? He is looking for around 750-800HP...

Looking for some dyno comparisons for him...New headers aren't really in the budget, and used headers just scare me...

If hes in fresh water, what about a set of lightning headers. No where near as spendy as cmi's.

We were discussing the lightnings. His dilemma is, 5-6k worth any power? Reversion and leaks are not a issue with his stainless marine setup....mainly just power

Stainless marine Gen III 4.5 in riser,,,, will never leak and your probably only leaving 5-10 hp on the table which in a boat is nothing....no loss in speed