I've got my Slot It GT40 and a Racer GTO250 that I've never been able to make competitive in the Gt class, but have always liked driving them down motored as a classic sports car.
Then there is the Racer Maserati 450 that doesn't fit into any other class but is a blast to drive. I did some research to see if anyone ever ran it in USRRC, but found that the Maserati 250 was run but apparently not the 450.
The class still has the 18K motor, the only difference between class 1 and class II is a podded chassis and 8mm tires rather than 7mm tires.
I know you have a couple, and Al built one out of a Monogram Corvette, Now there is a 3D chassis available for the Scalextric L88 Corvette, which with it's wide stance could be made very competitive. I think several of the guys have podded cars laying around that don't get much action.