I've searched both here and hybridZ and haven't found an answer, so I figure nismo or bleach might have an answer.

Has there been any testing on the stock exhaust manifolds as far as flow? I currently (still) have my intake and exhaust manifold off for a gasket change. I also have them taken off on mt parts car (both 79' S130's) and while I expected them to be the same, one exhaust manifold is rather small/compact while the other is a great big heavy thing. The small/compact one was on my DD with the round sleeved exhaust ports, while the large one has the square exhaust runners on them. I understand that I can use the square port one on my round port head, but would there be any noticeable difference, other than the location on the y-pipe and possibly moving the rest of the exhaust to accomidate the slight change?

No, I don't plan on keeping a stock style exhaust, I do plan on muying an exhaust system for it, but also am planning on a non-EGR intake at the same time, so I need to save up some cash for both, so I figured I'd see about these stock manifolds for the time being.

Any help/info is appreciated!