Marty,
I attempted to run an MRRC Chappy 2F body on a Slot.It GT40 platform, but the weight difference with the heavier MRRC body and higher CG with the wing made it uncompetitive when compared to a GT40. I have a white body Chappy kit somewhere, but I think it ran away with your BRM Leyton House Porsche kit. I’m really not sure if Russell ever got his Chappy dialed in.
Jim