I just kicking around the idea of throwing headers on the boat. Right now I have twin 454 mags. It has Gill exhaust. Have done some reading a lot of guys are saying its not much worth it unless your doing other engine upgrades. How much HP could I expect to see? Are they as simple as unbolting the manifolds and bolting the headers on and away you go, or it a tought job.?

Was more or less thinking if I could find some used ones at a descent price and netted me something worthwile maybe I would do it.

You might want to talk with an engine builder as far as real world results, as far as installation I installed 2 sets of CMI fusion headers in my Kachina. Using CMI's measurement guide they built mine & they bolted right in no problem. These are the new 1 piece header & tail combo. Randy

thanks . mine are in the boat which would make it harder, but I would think as long as you got ones made for it, it should be fairly simple.

Ive seen guys say 10 hp and other 40. For 10 hp i would probably not bother, but if I could get close to 40hp times two for two engines that might be worth my time

If you have Gils now and stock engines my vote is save your money for gas.

kind of what I was thinking, from what I have read GILs is pretty good for manifold

The Gill manifolds make an excellent exhaust. Keep them on there imo

with your engines,you will not gain any power,just bling,you can buy a lot of fuel for what the headers cost,just my opinion.

thanks guys, was just bored at work and looking into things, kind of mixed opinions out there on other websites. Probably not worth it at this point.

Man I need a job where I get bored at work.

I am with everyone else, wait until rebuild time and you bump the motors up.

Also changing them in the boat would be a PITA.