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On my '37 115C, should there be a gasket between the intake and exhaust manifold? I didn't see any evidence of one, but that doesn't mean one shouldn't be there.

Also, all three bolts holding the manifolds together were corroded beyond repair. My thought was that stainless steel would hold up better, but I was concerned about the differing rates of thermal expansion between the stainless steel and cast iron. Anyone have any experience with this? Per this table:

engineeringtoolbox.com/linear-expansion-coefficients-d_95.html

Gray cast iron has an expansion coefficient of 6, Ferritic SS has a coefficient of 5.5, but Austenitic SS has one of 9.5. Not sure what normal SS bolts are composed of.

Last question: the threads on the two bolt holes where the exhaust flange bolts onto the manifold are pretty weak, possibly beyond repair. Do most people use a through bolt, or attempt a heli-coil or some other repair. As always, thanks!

Yes, definitely needs gasket. I have a couple it you want, and don't twist the fork in my back too much, as I haven't put the wiring harness deal together yet. Soon "first chance I get"... DAF

Bump... any thoughts on stainless steel bolts and attaching the manifold to the exhaust pipe?

Flackmaster, don't worry too much about the harness- no fork in hand here! Still interested when it comes, but I'm in full crisis mode to get the frame done and car back enough together to drive onto a trailer and towed cross-country in 38 days. My plan for that is to just wire up the starter and coil temporarily to get it on the trailer and off again.

Ken, stainless steel bolts, nuts, and lock washers should work for connecting the exhaust pipe to the manifold. And, brass nuts on the studs for connecting the manifolds to the engine block.

(o{I}o)

I prefer brass nuts on the connection of exhaust pipe to manifold.