There was only one Whipple, the 1.6L, made by Lysholm in Sweden, used by Comptech in their standard supercharger systems. It was used from around 1995-2004 from memory. It can be distinguished by a black cast housing. It was replaced by a 1.7L Autorotor compressor, and then recently, this was replaced with the 1.6L 1600AX, which is very similar to the original Whipple. All three are very solid reliable units producing around 80-100 horsepower gains with the rest of the Comptech/CT-Engineering supercharger kit.
take care,
-- Chris