I believe the current ZR1s are supercharged, but the originals  were not, they were 5.7 L V8s, but not the regular smallblock. They were all aluminium castings, dual overhead cams, high reving monsters built by Mercury Marine. I believe the 512 TR was more from around the same timeframe as the Zr1s, , Not sure about the specs on it, but I do know they looked far better than the Testarossa. Still, I always preferred the real Ferraris with the V-12s mounted in front. After all, it was Enzo himself that said, "Its the horse that pills the cart."