Re: NHRA Stock/Super Stock Classification
 

IHRA Super Stock Production is pounds per cubic inch. Weight of the car with driver, divided by the cubic inch of the engine = the class you will run. If it fits into, say, SS/PAA-1 (7 pound class) with a 427, you would weigh 2,989 pounds.

In horsepower to weight categories, IHRA generally mirrors the NHRA ratings, but not always. As an example, the 1990's LT-1 in a Camaro/Firebird for SS/IA, it's rated 279 in NHRA and still at 275 in IHRA.

All the IHRA info, including people to contact regarding a question, can be found here.

http://www.ihra.com/competition/index.php

Re: NHRA Stock/Super Stock Classification
 

Bruno,

Actually there is no such thing as a "natural" class in NHRA SS/GT. Using the 12.98 weight break, the car's shipping weight is 2726. From there you can subtract a maximum of 250 pounds or add a maximum of 250 pounds to calculate what classes the car can fall in. With the maximum removal of 250 pounds the car won't make the top of GT/F(A) with the 230 hp engine but the car could:

run heavy in F @ 2670
G @ 2700
H @ 2815
I @ 2930
J @ 3045

using the 220 HP engine in would be:
heavy in G @ 2670
H @ 2700
I @ 2810
J @ 2920
K @ 3030
L @ 3140

This is using the data available as of today, 12/2/2010. Hope this clears things up a little.

Re: NHRA Stock/Super Stock Classification
 

so if t have a 83 grand prix (shiping w-3300) with a 327 nhra rated at 299
i can add 250 to it?
so 3550/299=11.87 which is gt/h or remove 250 and get 3050/299=gt/e
so i can run from e-h????

Re: NHRA Stock/Super Stock Classification
 

Yes, a 1983 Grand Prix Coupe 2 door Brougham's shipping weight is 3300. With a 327 rerated to 299 hp the car would run:

heavy in E @ 3220
F @ 3305
G @ 3455
H @ 3605