Does anyone know the type of exhaust the hp500 came with? Or an equivilant? Im going in with gm marine 502s (415hp) and was going to put the hp500 intake and carb setup from hardin marine on them. I have the CMI sport tube headers from my old engines but they dont lend themselves to installing a through prop switchable exhaust. Any recommendations would be appreciated. Thanks.......Casey

Hi Casey,
I think they are "proprietatary/Merc" (no big differences) CMI E-tops.
The sport tubes should be fine too. You don't need no stinking mufflers .
Regards,
Steve

Thanks Steve, I knew I count on you to throw some helpful info my way. Actually my headers are the big tube type for large displacement motors. I still have the reciepts for them from the prior owner and they cost 6,000.00 per pair. I figure I could sell them for half that (or less) to free up some money for other stuff. As Im staying in the low 400hp range, A swithable exhaust shouldnt be a problem. (I want to have stealth mode) What about the exhaust the 496 mags come with?

I think those were the 525 EFI's. The carb HP500 were Gil's, or 'Mercury Racing by Gil Marine' if you want to get technical.

The factory Mercury HP500 engines had problems with reversion and Mercury had to recall them and build specific tailpipes to compensate for the camshaft duration. Those engines will not except a silent choice style of riser that you are inquiring about with out having reversion problems. The manifolds were built by Gil Marine for Mercury Racing. We not only stock the Mercury Racing manifolds but also their sibling Gil version with all ranges of pipes. But keep mind if your running the 502/502 GM Performance engine or the HP500 their [email protected] duration will wreak havoc on your selectable exhaust choice. You may want to look into a selectable muffler/silencer offering to give you another choice?

Im running the 502/415. I thought if the 496 mags can run silent choice, then I should be able to. I guess I need to research A bit more and just use the sport tubes for know. Thanks for the input guys.

I have a 35 lightning with gill manifolds with stainless marine riser pipis with silent choice . also hp500s no problems. Tim

I have had a post on here concerning my HP 500 Gil Exhaust pipes feeling to hot, what should the temp be on those pipes? Mine is all factory set up with no modifications. Engine is cool and all good everywhere else, just the pipes not manifolds, feel to hot to me. Thanks.

I have a 25' Rage with a Whipple charged 496 (600+hp) and CMI E Top headers and silent choice. I have been running this setup for 5 years with no problems. I would not be without the silent choice, I seldom turn the noise on except when I am "making a statement". But that's just me.

I don't quite understand what that has to do with my exhaust pipes being to hot, but ok. I do not have silent choice, and I do not like it personally. But that's just me..