Twin H intake block off plate

dave11

I am in the process of replacing the intake manifold on my 52 308, still considering installing an exhaust header.
Anyway, I understand one of the faults with the stock exhaust manifold is the heat is transferred to the intake manifold via the heat riser chamber. I seem to recall a post where the fellow installed a metal plate to seal off the passage of exhaust gases up into the intake manifold. Seems like a good idea, wondering how thick the plate should be, also is it necessary to use a gasket on one side to stop exhaust leaks?
Wonder how a copper plate would work, may be able to leave out the gasket ?

super-six

I made one from stainless steel. One I had made earlier from sheet metal rusted-away.

50C8DAN

I have headers on my '54 with Twin H.  I have not had any issues with having the intake without any block off plate.  However, in the new 2x2 intake we are designing, which will be Al not cast iron we plan to offer a block off plate for anyone still using the stock cast iron exhaust manifold.    It will not be necessary with headers as there will not be any connection between the intake and exhaust with the new design.

dave11

Tks guys