Hi everyone newbie to the forum and looking forward to being an active part of this community! I am also new to the jet boating world and very excited to get mine going!

I recently purchased a 23' 1975 Hustler with a 455 oldsmobile engine and I have a few questions, hope someone can help me out here...

1. I am installing Hardin Log Manifolds and was wondering if they directly bolt to the block or is there a gasket needed? Checked out the Hardin marine website and cannot locate a gasket that matches my bolt pattern, so now I am a bit confused. I would think there would be a gasket between the manifold and block??

IMHO I have always made sure the gasket surface on the manifold is flat and used either high temp silicone (like Ultra Copper) or simply high temp never seize. The weak link is the center Siamesed cylinders. At the same time if you want to run a gasket I would recommend solid copper.

2. Can automotive parts be used on this engine or should i stick with only marine parts? Reason I ask is automotive parts are much cheaper than the marine parts. Not sure if it matters but I will be using on lakes and rivers only, NO ocean.  What parts?

Thanks

any idea where they may carry a gasket that would fit the HARDIN WET LOG MANIFOLD OLDS 455? Have been searching like a mad man but cannot seem to find one that will fit that bolt pattern, if not I may just have to go with the high temp silicone as you suggested.

As for parts... Carb, Distributor, plugs, plug wires. All external parts nothing internal.

Dont use a solid copper gasket . trust me been there done that. make sure the head is flat and the manifold is flat! i got away with useing felpro automotive exhaust manifold gasket with the RTV high temp sealer.copper color. good luck.

Ok so I went ahead and ordered the copper gaskets here... http://www.scegaskets.com/Oldsmobile/350-455-V8/Exhaust-Header-Gaskets/SCE-Pro-Copper-Header-p6630115.html

They are a soft copper so I am assuming if installed correctly the copper should form to any imperfections at the seal if any. Now when I removed the LOG MANIFOLDS there was no gasket, nor was there any sealant so now the question is install the gaskets or just go with the High Temp sealer? I don't want to run into any issues with the copper gaskets later on down the road creating to much heat at the seal

I guess it would of helped if I added why I was thinking about adding the gasket... When engine was running it was pushing a bit of air out the top of the manifold. Could have simply just needed a good tightening on the bolts, however I figured I would just remove it and see how the surfaces looked both on the manifold and the block, to me looked fine.

the copper gasket should have a little "ridge" that helps seal any imperfections.  you shouldnt need to run any sealant just make sure they're torqued correctly. according to http://www.442.com/tech/torque.html it looks like 25 ft/lbs.