ok i have gil exhaust for my boat would i have a better gain with something else, i run a 540 600 hoarse #3 speedmaster on a 27 magnum

I think CMI E-tops or Unitops would do everything you want for the 600 hp level. Stainless Marine's better offering with the divided riser/elbow would also be worth serious consideration. --- Jer

I am going to say go with CMI elbow tops. I have them on my na 540, 680 hp. I run them with full dry tails and GGB extreme mufflers. Works great.

will i be wasting money because i already have the gils, would they be sufficient or are they crap.....thanks also guys

I think a true tubular header like CMI would be the ticket.

www.custommarine.com

nocig, You'll get more of a "KICK" with a tubular exhuast system. The GIL's are okay, but they're only good to about 550hp from what I have heard, but don't know it if that is entirely true. However, one thing you can be sure of is that the GIL's don't have anything near the potential of a tubular exhaust system. So, you'd be much better off with a tubular exhaust system (especially on a 540cid engine) than you would with a GIL. Have Fun!

I would suggest Stainless Marine Gen III aluminum manifolds....they make more power in that area....I switched from Steelings headers to Gen III in my blower motors and I can definitely feel the difference. You also do away with the worry about leaking headers, WHICH WILL HAPPEN....good luck with the Mag,

Stainless Marine all the way. Lighter than tubular headers also. Eickerts manifold are really nice too.

I have stainless marine 3's with 5 inch tails on my single engine 27 foot v,they work excellent BUT they are absolutely humungous and were a lesson in misery,hacking and cutting to install. They look like crap too compared to nice headers. I'm not sure if I'd buy them again,Smitty

we had cmis, we had one leak, and instead of trying to find one to mathc we went with stainless marine gen III with 5 inch pipes....were still not sure how were gona fit six 5in pipes out the back tho