"Street Skinner" engine packages have been a product of Automasters of Bowling Green" or just "Automasters" when the business was in California. The first ones were done in the 91-92 period and they were done on a variety of different ZR1s from 1990 models to 1995s. Each one was a little different but included a "standard" core of engine mods: ported/polished heads, ported/polished housings, partially ported/polished plenum, reset cams and custom cal. Most Street Skinners were 350s and the performance of those varied from 475 to 530-hp SAE depending on whether or not the engine had stock manifolds and cats or headers and what kind of cat-back exhaust it had. Also some of the later Street Skinner 350s made a little more power as the package was developed over time.
Not sure how many Street Skinner engine enhancement packages were done nor am I sure how many were 368s, but the guy whose shop does them is Jim Van Dorn. He may know something about the history of the car in question.
Van Dorn can be reached at
jim@automastersofbg.com