Boring out "A" manifold to "B"size ?

[Terry NJ]

Thanks Brent, I looked at Joe's link and it all became clear. Any fairly sustantial angle plate would do. This is entirely doable for me.
Terry

Joe & David have pretty well covered your first 3 questions. The only difference is I do not detail (radius) the end of the draw tube because I am wanting the reversion effect. As for centering, IMO you need a lathe and a mill to make a plug. If you notice, Dave has a fixture to hold the manifold however it takes someone with machine experience to make that. I do not have a fixture for modifying manifolds but I just make a plug.

As far as how to port match, mount the manifold to the block without the intake valves and stick your finger down the pocket area and feel with your finger.

 

[Terry NJ]

Joe, About a hundred or so years ago, I ported and polished a couple of flathead V8s. For port aligment, we used a gasket and a pencil. I really didn't know what kind of a finish was necessary(or not necessary) so I brought them to a fairly high finish with a small drum sander (?) At what point are you overdoing it? I had taken all casting defects, aligned the block ports with the manifold and polished them to a high finish. It was a lot of work for what seemed a small gain.
Terry

If the manifold is fairly clean and dry, a quick shot of spray paint should give a good outline of the block against the manifold surface. Same for exhaust.

Joe