Originally Posted by Bill Harris

Here is a handy excel spreadsheet I made for figuring out which GT classes a particular chassis/engine combination can run. It calculates the minimum race weight for each class and shows the ET's for the class index, 0.8 under, 1.0 under and 1.2 under. It also does an estimation of the HP needed to achieve the ETs at the min race weight. You only need to enter the body style shipping weight and the NHRA factored HP for the engine you want to use, and if it is a stick or automatic. It will do all the calculations in any easy to read and print format.

The numbers that are in this copy are for a 2006 Chevy Cobalt 2-door LS coupe with a 1987 305/170/271engine with an automatic. Just change the numbers for your engine/body/trans choices.

Enjoy.

http://www.employees.org/~bhracing/g...calculator.xls