Might as well cover this here, in case anyone else is interested. The rest of you class racers jump in and correct me if I lead him astray...
First off, take a look at the
NHRA Stock Car Classification Guide. This will provide you with the current HP factor, from which you can figure your minimum weight and your class. I'll use the L-72/400th as our example.
From the link above I select "Chevrolet, 1969", which will open the page for all 1969 Chevrolet combos. Then, I scroll down to "Camaro", to "Coupe w/TH", which is the L-72/auto combo. It tells me it has an "8.06 lb per HP" factor, and is factored at 425hp. Now, with that, I look in my NHRA rule book (thanks Barry!) and it tells me that it falls in "A-stock", which is 8.00-8.49. Now I can figure my minimum weight. Since it's a natural A/S car, I can use the class minimum weight factor of 8.00. Multiply 8.0 by the Hp factor (425), add 170 for driver, and you get a minimum weight of 3570. NHRA also allows you to drop down 1 class by adding weight, which means since it's a natural "A" car it can drop to "B" by adding 212.5 pounds.
See, clear as mud! [img]/ubbthreads/images/graemlins/grin.gif[/img]