Dave I had carb. off intake and it did not look to be a re-drill or welded -- it has a 2 7/16 center to center on studs. But bores are not the same -- runs OK. intake looks like an un-modified stock PA.
The Pattern for the heat shield is for a stock PA carb. very different from the BB1 and I modified it 3 time before I settled on this one, many changes. Most of them I made on the fly. When I have it off next time I could copy it.