Exhaust Manifold Question/Help

[tgilmore99]

I had a small leak occur in the exhaust manifold. So I ordered the parts and put them on. I saw that there are only 5 bolts holding the exhaust manifold on. Not 6 bolts. There is not a hole for the 6th bolt in the manifold. Is this normal? My boat is an 85 sundancer 270 with twin 5.7 OMC is stamped on the manifolds. I am not sure if they are factory or not the previous owner may have had work done to the boat that I don't know about. Both engines are the same way though but only one manifold leaks. Does my explanation make sense? Any help? Thanks

 

[Cap10Pat]

I'm not sure what your explanation is, and not familiar with the OMC. You didn't say if your manifolds were ordered from the factory or not. I think that manufacturer has changed since 1985 anyway. So manifolds may well be different. Leakage is usually due to bad gaskets, but you can also have warped, damaged or poorly cast manifolds. Also make sure everything looks right. And check the engine as well as the manifold. that could also be damaged. Try to remove the manifold carefully and examine the gasket.

 

[tobnpr]

Without knowing any of the specifics of your engine, far as I know you're talking about a 350 c.i. block and there should be six bolts?

In any case, if there's six holes tapped into the side of the block, you need six holes in the manifold! There could very well be changes in the riser design from your old ones, but the manifolds should fit any 350- regardless of who marinized the block, far as I know...

 

[penbroke]

Which one is missing? I'm thinking there should be 6 as well.

Frank
Just curious...