Were any but the Buick V6's and their progeny 90 degree engines? If not, then it should be pretty easy to pick out the old Buick or the Buick/Kaiser, since their peculiar layout required the distributor teats to be unevenly spaced.
I think Ford had a 90-degree V6, and the ChryCo 238ci V6 is based on the 90-degree LA Block.
And don't forget - there were
two versions of the old 231ci Buick - the odd-fire and the even-fire. The "odd-fire" is considered the stronger of the two, and I believe the G/N twin turbo version was only had in odd-fire.
Why is it stronger? To get the "Even-fire" crankshaft, it required splitting the crankpins and offsetting them. I don't have any good pictures of it to hand, but the "even-fire" and "odd-fire" cranks can be readily told apart - the "odd-fire" looks like a shortened version of the typical V8 crankshaft (two cylinders per throw, common pins,) and the "even-fire" still has two cylinders between each main journal, but they are no longer on a "common pin" - there's a "web" between "pin halves" (sorry to quote so much, but I'm stuck trying to explain it without a decent picture...)
However, the engines may be readily identified simply by looking at the distributor cap - if it has the correct one on it. The "even-fire" cap has the towers arranged 60* apart, and the odd-fire has towers at intervals of 0-45-120-165-240-285-0* (45*/75* splits.)
Why is this so? The "natural" bank angles for a V6 block would be 30*, 60*, or 120*; while the "natural" bank angles for a V8 would be 45*, 90*, or 135* (multiples of 30*, vice multiples of 45*. In both cases, the second is the best of the lot. Oddly, just about all
even numbers of cylinders will work out with an included bank angle of 180* - or horizontal opposition, akin to the Folksvagen, Porsche, Lamborghini, and Corvair engines.)
