To calculate GT combinations:
1) Go to
www.classracerinfo.com
2) Register as a member if you have not done it already
3) Go to link for Technical Tools
4) Select NHRA Classification Tool
5) Select your car year-model (1971 Plymouth, 1987 Camaro, etc) from the drop down boxes
6) Click on the specific make-model-engine combination from the classification page (looks like an NHRA class guide page)
7) You will see Stock-Super Stock classfication information. At the bottom of that classification information page is a button titled "GT Classes". Click on it.
8) Select the engine you want to use from the list that is displayed and click on the button "Classify"
9) Ta-dah! All the GT classifications with weights, classes and indexes for each eligible classes.
