Exhaust manifold glands

[JayJay]

All, good day.

On the Model A engine, there are metal glands that insert into the exhaust manifold and also into the exhaust ports on the engine block. When installed these glands keep the manifold exactly aligned with the ports. The width of the glands somehow relates to the depth of the recesses in the manifold and block, plus an allowance for the gasket thickness.

What I'm after is the relationship between the width of the glands and the depth of the recesses. I need to deck my manifold assembly to get it flat (and get rid of leaks), and I realize that I need to decrease the width of the glands appropriately. But how much? If I had an unmodified engine I would simply reduce the width of the glands by the amount the manifold decking removed, but my engine has been rebuilt and I presume that the manifold mounting surface was decked at that time. And I'm not sure that the present width of the glands is proper. So my "original" manifold+block combined depth is lost forever.

Should the glands allow the manifold to sit flush without the gasket, so that when the gasket it installed the gasket is allowed to crush? Or should some allowance be provided for gasket thickness (say, half of the uncrushed thickness??)

Or, does anyone know the original depth of the block recesses? I can measure what I have and deal accordingly.

Thanks, all.

JayJay