[Bob Bidonde]

If you leave-out or loose the 2 bolts connecting the intake manifold to the exhaust manifold, there is no need to machine the manifolds flat. Doing this results in a gap between the hot spot surfaces, and increases cold weather warmup of the carburetor.


The exhaust manifold gasket must be metal to withstand exhaust gas temperatures. Also, the gland rings protect the gasket from burning. Be sure each gland ring, when installed, has a gap at its ends of 0.06" minimum to allow for expansion.


The large washers that bear against the intake & exhaust manifolds are actually cupped so they are springs. OEM washers were actually made from leaf spring stock. The concave cup faces inward. Do not torque the washers flat.


The clamp supporting the muffler pipe needs to allow the pipe to move through it, and to twist in it to account for thermal expansion of the pipe, and twisting of the car's frame. If the pipe is tight in the clamp, the exhaust manifold will experience excessive stresses at its bend. The excess stress leads to warping and eventually cracking of the manifold.