 Although power was up to and of torque, 1990 saw the lowest number of (B2K) Callaway Twin Turbo Corvettes ordered with 59 with only 58 actually built.To counter the ZR-1, for the 1991 model year, Callaway was able to bring up the output of the B2K option up to and of torque.1991 would be the last year of the L98 engine which was the base engine of the Callaway Twin Turbo Corvette.