90profx

The actual length you see covers the exhaust tube from the OEM riser HUMP hose connection to and including 6" aft of the transom. One pipe non-stop out the back

Ryan00TJ

iTrader: (8)

Gotcha. Fully dry setup. Nice.

90profx

Update for this Tuesday:

Both risers back from the chem strippers, perfectly clean inside and out:







Weld shut OEM Riser water transfer ports:








Machine holes for stainless water transfer elbows to tailpipes:






Position & tach weld water transfer elbows on location:









You'll notice that I cut off the flared end of the OEM Riser exhaust pipe as there's no need for it since it's now a 100% totally dry pipe and to ensure there is no contact with the ID of the tailpipe.

Ryan00TJ

iTrader: (8)

Looking good. Risers look awesome. Do you plan on removing the turbulators between the riser/manifold? Dyno proven 8-10 hp gain thru the rpm range. Most notable is the 25-30ft lbs torque gain from 300-3500rpms on the 496HO.

90profx

Thanks, yeah, the risers were freak'n spotless clean, I was amazed how clean they were !!!!!
I've not even looked into the Turbulator yet, I have the 496 MAG motor, wonder if results are close to the same ???? I'd think it'll probably be worth something extra in power department wouldn't you ? I'm still deciding what to do on the transom end with the tailpipes.........weld on a flange or use a Beauty Ring w/Silicone Gasket.

90profx

Just took one riser off the motor and looked over the TURBULATOR issue in comparison to the actual exhaust opening.................that's a Merc part that's not going back in again........WOW, what a restriction that part is. Obviously now being a true dry system, there's no need for it anyway as moisture is no longer a concern in the exhaust system. I've order a pair of 6" OD x .25 THK 6061 Aluminum discs that I'll be machining for the tailpipe flanges. Also ordered some high temp silicone sheet at 1/4" thk that I'll be making the tailpipe flange gaskets out of, it'll serve as the water tight seal around the tailpipes as the tailpipes are not going to be welded to a flange, they'll float being supported by the silicone gasket alone. This is how the marine industry Beauty Rings are made as well so I'm just copying their concept.

Now onto my dumb move ................As I was pulling the port riser off, I managed to drop one of the flat washers from the riser down the exhaust manifold......."TOTALLY DUMB MOVE ON MY PART", I thought I had them all off the studs. It's not visible so I'm going to borrow a buddy's flex neck camera to see if I can determine where it's at before I do anything else. Hoping it's not in the motor (a.k.a. exhaust valve wide open), hoping it's just laying near the head where it meets the manifold port. If that's the case I'll hand crank over the motor to ensure exhaust valve is fully closed and start trying to fish it out, or I'll have to pull the manifold off.

This is when I wished the washers weren't stainless as a flexible head magnetic would get-r-done. Chit happens, but why me as the o'l saying goes............... I made note of this just to prove that everybody has one of those days now and then and no one is perfect by any stretch !!!!!!!!!!!!!

class6

Why don't you take the manifold off and figure out if you really need the bottom valve. you might get better flow without it. running CMI's they tell you to plug it off. I think its a drain back when therei s no flow to empty the mainifold

90profx

Do you have a link to share for the CMI instructions ?

90profx

FYI Update on POST #46:

These flappers I used in post #46 are JUNK, burned up after one season of limited use.

class6

They are on the cmi website. http://www.custommarine.com/pdf_docs...osport_ins.pdf