Ken Robinson on the board here has a 1987 Turbo Coupe T-Bird that runs in Stock. ( same as the '88 TC)
I wasn't aware someone could run a 4 cyl. turbo combo in the SS/GT classes. I thought the GT cars were V-8's only.
At least that is the way I interprupt the rule book. ( the bold type highlighted below)
Copy and paste from the 2013 rulebook:
Requirements and specifications for GT classes
are the same as those for Super Stock classes -
Section 11A - with the following exceptions:
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