222rwhp! boy is my face red.

My first thoughts are too much carb, too much cam, and the manifolds... I'd swap the cam for something like the small Summit cam. You say there's no room but tthey are center dump... Can you have a shop remove a section of the manifold and re-weld the flanges so you have som room to run a decent pipe? I would concentrate on the exh. I don't believe the convertor is a problem if you made a few tuning changes and the dyno showed the change. When a convertor is messing with the results it doesnt matter what the engine's doing, the dyno won't really show much of a change. I have a '65 A and I plan to run oval tubing as large as I can fit for the single pipe with 1/4" larger than the manifold outlets (small block going in).