[SSSammy]

Before you get too wrapped around the axle .. open the hood and tell us if you see aluminum intake and aluminum heads. If so, it is probably a modern engine rebuild on a vintage block, and you can run unleaded 93 and not worry further. If you see iron intake and heads, then all the above advice applies.

Sam

P.S. Go to the Lone Star Forum here and also their factory site and intro yourself and ask if anyone knows your car. Give the chassis number. There aren't that many of them, somebody will recognize it and be able to give you some history on it. Failing that, call the factory and ask Brian the same question.