Originally Posted by Ryck Campbell (Post 411897)

shipping weight of the heaviest V8 for the year, make and model of your car; subtract 250 pounds then divide by the factored horsepower of your engine to calculate the lighter class OR add 250 pounds then divide by the factored horsepower of your engine to calculate the heavier class. You should come up with between 3 to 5 classes that your combination can run. THERE IS NO SUCH THING AS A NATURAL CLASS FOR GT. An example could be as follows:
1973 Corvette coupe with automatic - shipping weight is 3559 so 3559 minus = 3309 or plus 250 = 3809. If you use a 1969 350/255 with OEM heads the factor is 294. 3309 divided by 294 = 11.25 (this combination CAN NOT get to the top of the 11 pound class, GT/GA) so to run GT/GA the car would have to weigh 11.25 times 294 plus 170 = 3475 rounded down from 3477.5. For the heaviest class the car can run is 12.50 class, GT/JA or 3845. Obviously the can can also run GT/HA @ 3550 and GT/IA @ 3695. I hope this helps.

Ryck Campbell NHRA D1 Tech Director
315-335-8295