I've said I wouldn't do the under manifold heat thing till I needed it. Tried to no avail to find an aftermarket piece, can't find one. 67° is the temperature for me when I decided I needed to make one. I'm trying to do this without disassembling the intake. Everything else is ready, just can't match the single bolt . Anybody off hand know the size of the single bolt under the offenhauser intake? Every bolt I know about and have doesn't fit.