Barbara_S

Does anyone here know the real history on why the ZR1 is on a separate line (while the Grand Sport is not) for C4's in BSP? I've wondered if the SCCA separated it way back in the 90's because of power alone and since I own one I'm curious if anyone knows what the real logic was on keeping it separate from all other 84-96 cars.

Solofast

The reason it is on a differnt line is that they figured that if they put it on the same line, that a ZR1 motor would end up being a requirement for the class. The ZR1 was a pretty heavy car and the engine doesn't really make up for the lack of front end grip that the weight causes. But if you could update and backdate that motor into an 84 chassis...

A blueprinted LT4 makes 400hp. A blueprinted ZR1 motor would probably make about 450...

Well, you get the idea....

UstaB-GS549

The ZR-1's were 375 & 405 HP and the GS was 330 HP. The rear track is wider on the ZR-1, but the tire sizes are identical. Supposedly the ZR-1 weighs more.