Has any one had or heard of these manifolds causing problems with water reversion. A salesman for a major shop told me to avoid these as well as the units used by merc in the 500hp. Mind you he only sold EMI and CMI.
Im trying to find a set of manifolds for my 502 and dont want any trouble.
thanks SJ

Oh .. by the way. Anyone having manifolds to sell , please let me know. sj

My son has a 21 ft. Stryker with Gil exhaust no problems

stevejohns,

The problem isn't so much the header as it is the cam used on the 500 HP and 500 efi engines. The reversion is generated by the overlap of the camshaft and will happen with virtually any exhaust manifold design. Some protection is gained thru the use of a manifold with built in anti-reversion flaps or transom tips with build in anti reversion flaps such as those made by Stainless Marine, Corsa and others.

Good luck,

Steve

What this guy told me was.. That the Gils had the water injected into the manifolds much closer to the ports than EMIs or IMCOS. This he cliamed was the reason for the water injestion. I have the anti backwash tips on my boat.
Thanks for the help guys

How about if you run Dry Exhaust, Does this eliminate water reversion??

I run Stanless Marine and my water is introduced eight inches from transom so this factor is increased and I run Drew shotguns with it in the the hole that gives the most back pressure. Dry pipes no reverson

I have Gil Wet Offsshore manifolds and risers. NO problems to date. Personally, I like the idea that NO water passes through the riser gaskets, the by-pass hose system to me is a great idea.

stevejohns,

I have known many folks who use Gil manifolds and pipes with no problem... Until this boat I used strictly dry pipes, however, presently have an application which has three sets and no problem what so ever... Gil normally provides "turbulators" for each tail pipe which they say helps to minimize this issue... Now if the tail pipes or manifolds are leaking that is entirely another issue which may also be the case with a really radical camshaft...
There are much more radical applications than the HP500 and EFI out there so would imagine that some of the members could also comment on that...

Tnx, Karl

I'm running the Merc/Gil exhaust with silent choice even, so water is exited out of the risers even closer than straight thru hulls. I have no problem with reversion. Also running a cam with a lot more lift & duration than the HP500's.
Me thinks his "salesman" pitch was doing the talking.

Jerry