[Adger Smith]

I think if you figure the 12.71 factor of a M/C SS with the super stock 259 factored HP of a 305/190 Auto. With the 330 hp GT factor of the 327 you will find:
12.71 X 259 = 3291,89 as the base weight

Class- class brk - Car weight - race weight w/drive

C - 9.0- 9.49- 2970- 3140.9
D- 9.5- 9.99- 3135- 3305.0
E- 10- 10.49- 3300- 3470.0
F- 10.5- 10.99- 3465- 3635.0
w/after mkt heads 335 GT HP factor
C- 9. - 9.49- 3015- 3185
D- 9.5- 9.99- 3183- 3352.5
E- 10- 10.49- 3350- 3520.0
F- 10.5- 10.99- 3518- 3687.5

D would be the base class
It looks like C would excede the 250 weight limits from the base weight. the way I read it the weight/class is of the car before the driver. His weight doesn't make the class only race weight.