Going to upgrade 98 head and cam on carbed 500's, the exhaust are the gills with stainless risers, is the exhaust going to hurt performance, I noticed the risers have a large sweep to them so I don't think reversion should be a problem. I wish I had the CMI that come with EFI's, was the big change for weight of the reversion problem. any help would be appreciated

thks Joe

Joe, I think the GILS are about 25-30hp or so less compared to a tubular exhaust system so, that isn't so bad. The GIL's are a MUCH better system than the stock Merc cast iron exhaust system! If you want, you can have them totally converted into a DRY system which will eliminate the chances for reversion and actually give you a little more power by doing so. The GIL's should continue to help you realize any performance mods/upgrades you are doing and still be able to breath decently. Yes, the CMI's, Stellings, etc, are nice, but if you already have the GIL's then I wouldn't sweat it too much---just my .02 of course.

I know of a friend who's got a pair of the Merc carbed HP500's with GIL exhausts and he's also doing some head/cam upgrades to them as well. He's going with an aluminum head, and hydraulic roller cam upgrade that "rmbuilder"/Bob is engineering for him. Bob would be a good person to contact/PM.

Hardin Marine makes a lower tubular S/S header that is a direct replacement for the Gil's. If your risers are good its cheaper and easier than redoing the whole exaust.

Guy's thanks for the info,

Joe