I have been working on my exhaust tubing for my warlock and have run into a little problem I need some advise on. My manifolds are stainless marine gen-2's. I have a s-bend behind each riser (consisting of two 90 degree stainless steel elbows with a piece of marine grade black hose connecting the two elbows). This places my exhaust behind my distributor where it connects to my tips with more marine grade black hose.

My question is this, I am EXTREAMLY concerned with reversion at this point for 2 reasons. (1) I have just switched my cam from the stock 454/330hp cam (214/218° @ 0.050) to a crane cam with 228/236 duration at 0.050 (2.) My risers are not very long. I'm considering changing the risers to a dry style riser to prevent this possible problem but I'm not sure what kind of heat I'm going to get through the s-bends and marine grade hose with it being dry or if it's going to melt the marine grade hose. It's been suggested that I drill some holes in the end if the "dry" risers where they're welded up to allow some water to cool the s-bends and hose. I'm also not to thrilled about drilling any holes in my boat for the water from the risers to exit through so I came up with another solution for that....I was thinking about tig welding a bung into the side of each exhaust tip (before the flapper / inside the engine compartment) and routing -12 hoses from the bungs on the risers to the bungs on the tips.

The dry risers would prevent any chance of reversion but like I said, I don't know what kind of heat I'm going to get from going to a dry system or if introducing even a small amount of water into the system though some holes in the end of the risers is going to cause a reversion problem. I have a sure solution for this problem which is to have stainless marine build me a custom set of risers but that comes with a $1,300.00 price tag which I would really like to avoid if possible!

Any advise or input on this would be greatly appreciated! Thanks, Mark

Any rubber hose in a dry system is going to melt. The cam you're looking at isn't all that big. I'd give it about a 50/50 chance of reverting. Maybe you'll be good to go. If not, custom tailpipes are the way to go.

Which Crane cam??? Whats the lobe sep???? Post a pic of the exhaust risers.

Hey Griff,
The cam part # is crane cams 132561. The Lobe Separation is at 114.

Here are the links to see a pic of the two different risers I have to choose from (the stainless risers are 17" long end to end and are dry. The aluminum ones are about 5" shorter)

http://www.facebook.com/photo.php?pi...&id=1057536260

http://www.facebook.com/photo.php?pi...&id=1057536260

I know in talking to S.M. recently myself with a poss. similar problem, one way they told me to pretty much eliminate the poss. of reversion is to simply put a set of flappers on the end of your pipes. When the flappers close ( at the drop of each lope) they stop any suction of water.

Are you talking about at the end of the riser? If so, I wonder how much heat you would get there and how long before the rubber liner on the flapper would be toast? Interesting thought though!

I think you will probably be ok with the shorter wet risers and a 114 lob sep. Setting the idle on the high side, around 900rpm in neutral, will also help reduce chances of reversion.

Yes on the end of your riser tube, they should handle the heat fine with the cool water mixed with your exhaust. I had a set on my old boat ( 400 hp 454 ) and my tubes were only 2 ft long and i had no probs whatsoever.

I am not sure I am following you. If you put flapper on the end of your riser and they are cooled by the water in the pipe then the water is already there to be sucked back into the engine. I believe the flappers you are describing are to prevent water from coming in from wave action while beached or following seas.

This one is pretty much good exhaust. Assuming that you would sell it, how you would like to sell it?