MittenHed: That's precisely my problem...I'm too lazy to go about looking and measuring, then fabricating and hoping that I didn't bollix up the whole mess to the point of no return. Preliminarily, at least, I had thought that a narrow GM 6, a straight 6 from a Ford, as you suggest, or perhaps even a vintage 2.8 V6 from an old Capri (which was very successfully tuned for racing) might fit the bill. But again, I'd rather consider the project if it was done correctly by someone else. I'm not that adventurous to think I can successfully fabricate what's needed to do it right.

Brad