I'm changing from the stock exhaust on my 454 to the short runner 496 manifolds. These manifolds have some sort of one way check valve under the manifolds on the water inlet. My old manifolds don't have this.

I've been trying to theorize what these do, but am at a loss. The diagram I found doesn't say where they go to. Anyone have any idea? They seem to prevent water from entering the manifold from below, but allow water to flow out.

thanks

Here is the diagram if you need it.

I removed the check valve and put the 90° fitting from my old manifold in thier place. Ran all summer with no problems.

Did you take the turbulators out?

Let me know if you need more info.

Thanks, I do have that diagram, but I can't find any reference to where "C" goes. Any idea?

Sounds like it didn't do any immediate damage by taking them out, but I wonder why they're there in the first place, but not on the iron manifolds.

I run all my cooling into the bottom of the manifold and it flows out the top. Flow out the thru-hull exhausts looks nice and even.

The check valves at the bottom are supposed to allow the manifold to drain after the engine is shut down. They are only used if you have the air actuated drain system. Just replace them with an elbow.

Dave