I have hp 500 with merlin heads, and a couple of tricks done to it . I have glm exhaust with hardin risers 4 inch . I have been told if i want more mph i need better exhaust . looking for a good priced answer , even used

If your looking for a manifold style then hands down stainless marine I've run two motors with stainless marine, 1 with Eddie marine thunder , and the S.M. Is awesome, if your looking for header style ive heard cmi is the way to go however If your lookin for a cheaper route I have a set of Eddie marine thunder manifolds I'd be willing to sell and they have the oil filter and shift cable brackets

I have 2 sets of CMI that are new in the box, give you a great deal.

Just my two cents but I don't think you will be getting a whole lot of extra speed with this mod. I would spend the money on a good used charger and use the GLM's.

i have 1 inch shorty on it and i turn a labbed 30 pitch to 5150 and 82.5 rev limiter is set at 5350

best speed prop they say i am choking the motor i have those big chamber grumpy jenkins heads and 731 cam dart intake , full roller just trying to pick up 2 or 3 i dont want to buy anything that was in salt water