3.0L GM Industrial Engine?

[Gilby]

My first mistake was buying this motor without fully checking out the seller. I was supposed to receive a drop-in long block replacement for my blown 3.0 but found that the cylinder head has 6 ports (intake ports combined) instead of 8 and the exhaust ports do not align correctly with the manifold exhaust ports. I know that the newer GM 3.0's have a different head, but they are still 8-port. Of course the seller has disappeared and I can't get any help from the OEM. I looked up the engines on the GM web site and found a picture of my cylinder head - in the industrial engine section. The seller swore that the engine was marine with a stainless steel head gasket. The freeze plugs are brass. I'm trying to resolve this mystery and would really appreciate and help or comments. Has anyone heard of this? Does this sound like an industrial engine and will it be worth it to "complete" the marinization of it? It actually ran quite well for most of the season except now the manifold gasket has burned through because the ports don't line up. Is there a part that will "convert" the 6-port head to the 8-port manifold? Can I use the head from my old 3.0 on this block? Thank you very much for any information you can give me. I really appreciate it.

[george allard]

They make 4 different manifold gaskets for this engine. Try a NAPA store. It will work with the right gasket. We had the same problem.

[Gilby]

Thank you very much for your response. It did work great for most of the season but now it sounds like there's a ball-bearing pinging around in there - but only at max RPM and only after a few minutes. It has also developed a puffing sound - exhaust pushing out between the manifold and the head (I think). I think the pinging is happening because the gasket burned through and exhaust is crossing over to the intake at high pressure and temp. Even if the gasket was right, I'm still quite confused. Since 2 manifold exhaust ports don't line up properly with the head exhaust ports, the exhaust clearance for 2 cylinders is cut by about 30% to 40% - won't that cause problems from increased pressure? Last but not least, the cylinder head is noisy even without these other issues - lots of "chatter" under the head cover - but everything looks and feels pristine - Do you know what is the story with this 6-port head? Thanks again.