The old str. 6's had a fuel distribution problems as stated above. The newer ones have solved that problem w/fuel injection.

The str. 6 has a better balance(smoother running) & seems to produce more power per cu inch. Chevy has brought the str 6 & 5 back.

Thus,if you are going to install a older engine I would pick the v6, for a newer engine I would pick the str 6.