Hey gang, I need a little help with the install of the stainless
marine exhaust manifold's on my 377 Scorpion.

My engine has 2 hoses going from the thermostat housing on each side. (4 hoses total)

1 going to each stock riser, and 1 goint to each stock manifold.

WHY?

Does water not go through all of them at the same time if the engine is cold?

Will I still use all 4 of those hoses and just route them to the new manifolds......... and keep the little jumper hose on the new setup from riser to manifold......

Thanks!

Thank you!!

One hose on each side is a bypass that always has water flowing through it. On my Gil system they supplied a Y fitting that tee'd the 2 hose together which then went to the bottom of the manifold. Aluminum melts at a fairly low temp so you want to be sure you always have water flowing through the manifolds.

Speed,

How did the Stainless Marine manifold install work out? I'm going to change the manifolds on my standard 6.2s. I assume the heads and exhaust ports are the same between the Scorpions and regular 6.2's. I called Stainless and they could not tell me if the mainfolds would fit the 6.2s nor did they know if I would need to reprogram the ECUs. What has been your experience?

The two hoses that go to the risers are connected to the raw water bypass, and these are open when the thermostat is closed and then when there is high pressure in the system due to speed. At low speeds when the thermostat opens, it dumps water into the bottom of the manifolds and the spring loaded balls in the bypass system close so that water is not recirculated backwards from the riser into the engine. This is how a stock system works. Aftermarket systems should come with a recommended plumbing system, to keep the warranty valid. When I ran SMarines on my 406 small block, I ran the cold water bypass to the riser with my own y-connection but I think that PsycoStroker has a better Idea and run the tee to the bottom of the manifold so that water is always flowing through the manifold. Be sure to keep the balls and springs on the cold water bypass so that you don't get recirculation however small that chance is.

There were no instructions, no kit for this mod? It is unbelieveable that SM would sell these manifolds that need to me messed with in order to get it to work right. So ridiculous, so shoddy.

From SM manifold instructions: If your thermostat has two hoses to each side, call us and we will send you two more 90 degree fittings for the bottom of the manifold.

Some of the 6.2 heads have Ford style (equal spaced ports) outlets. None of the standard small block Chevy manifolds will fit.

Brownie,
My 6.2's have siamesed middle exhaust ports, so they should be the standard small block GM heads. Will the small block SM manifolds fit? The stock set up uses the standard Mercruiser manifold with a 3" riser spacer and standard cast riser. The stock set up gives a very slight downward angle to the exhaust hoses which exit straight through the transom. Will I need anything special to the standard SM small block kit to match up and install corretly? And, if everything else is stock except for the SM manifolds, will I have to reprogram the ECU's?

Yes, they will take the standard small block setup. I can't keep up with all the programs. So far, no one has had to reprogram for this setup. We have a standard short riser, 3" taller. The end of it points down at 13 degrees (perpendicular to the transom).