Not sure what the NHRA shipping weight is for your car...but, if it is 3400 lbs: then:
Your natural class @ 10.2 lbs would be GT/E
You could go to D @ 3325 + 170.
So 3495 lbs raceweight would be the lightest ?
From the 2013 NHRA rulebook:
DESIGNATIONS
GT/A, GT/B, GT/C, GT/D, GT/E, GT/F, GT/G, GT/H, GT/I, GT/J,
GT/K, GT/L, and GT/M, preceded by car number (manual
transmission). GT/AA, GT/BA, GT/CA, GT/DA, GT/EA, GT/FA,
GT/GA, GT/HA, GT/IA, GT/JA, GT/KA, GT/LA, and GT/MA,
preceded by car number (automatic transmission).
Reserved for foreign and domestic factory-production two-door coupes,
two-door sedans, sports cars, convertibles, or station wagons with any
production V-8 engine of the same make. Year of engine optional. Only
those engines and/or bodies listed in the Official NHRA Stock Car
Classification Guide are eligible for competition. Also see WEIGHT. Cars
will be classified using the shipping weight of the body divided by the
horsepower or performance rating of the engine used. Factory
production rear-wheel-drive cars must have originally been equipped
with a V-6 or V-8.
Front-wheel-drive conversions permitted. Minimum weight with driver:
2,670 pounds. Only engines and/or bodies listed in the Official NHRA
Stock Car Classification Guide are eligible for competition.
CLASS WEIGHT BREAKS
(based on pounds per NHRA-factored horsepower)
A: 8.00 to 8.49 F: 10.50 to 10.99 K: 13.00 to 13.49
B: 8.50 to 8.99 G: 11.00 to 11.49 L: 13.50 to 13.99
C: 9.00 to 9.49 H: 11.50 to 11.99 M: 14.00 or more
D: 9.50 to 9.99 I: 12.00 to 12.49
E: 10.00 to 10.49 J: 12.50 to 12.99
REQUIREMENTS & SPECIFICATIONS
ENGINE: 1
ENGINE
V-8 only; must be same make as body. Year optional. Engine must
be listed in both the NHRA Stock Car Classification Guide and
NHRA Blueprint Bulletins. Corporate engines permitted. Truck
engines prohibited. Underhood modifications for engine installation
prohibited (i.e., firewall, shock towers, frame, excessive cutting of