any horsepower or performance difference between dana, eddie marine with regular aluminum risers or stock merc aluminum manifolds with stainless steel risers. looking for best bang for the buck for twin 454 gen iv set up with 500hp a piece. still wanna keep my corsa silent choice.

best value for manifolds in my opinion are the reveloution marine. they sell direct.

Consider the the KE's. No leaky header issues, and have shown to be good performers.

I'd go with the Imco Powerflow Plus- or maybe just regular powerflows for that app.

This is pretty much a question of runner length & inner diameter and the PF plus's are really nice.

Ive got decades of experience with their products and they have been phenomenal.


UD

I ran a set of these on a 540/ 600 hp. I ran in salt water for 3 seasons, and then fresh for two more before selling the boat. I flushed after every run, and had no problems with them.

I know a few people that have well over 10 years on Stainless Marine with no issues (me included). And they flow well (no RPM loss vs. CMI headers on 500 HP)

I just replaced my Stainless Marine manifolds after 10-12 years of use. Hoping to get another 10-12 out of these.