Super Stock classification

[ss3011]

Originally Posted by bestephen

I can follow the Stock and super stock classifications its the GT classes that I don't understand. Say I want to run a 352 engine in a 1968 Mustang. How do I determine the class?

Get the shipping weight for the 1968 Mustang ( with the heaviest engine ) , then get the shipping weight classification sheet for the year of the 352 engine you want to run . Some times the GT engine is factored differently than the Super Stock engine factor . Once you figure out the engines HP factor then the natural class is the Shipping weight of the car divided by the GT HP engine factor . This gets you your natural class which you can adjust to the bottom of the class . Minimum weight for that class across the scales requires you add an additional 170 lbs. You are allowed to go up one class and down one class , but that's another discussion .

[Travis Miller]

To figure a car for SS/GT you first need the shipping weight of the car. Ex...1968 Mustang hardtop (coupe) with heaviest engine as found in the NHRA Classguide weighs 3253 lbs.

Next you need to find which engine you want to run in the 1968 Mustang hardtop. Ex...1964 Ford 352/250 engine. Again you go to the NHRA Classguide this time using the 1964 Ford page. At the top of the page you see the GT ratings for 1964 Ford engines. The 1964 Ford 352/250 engine is de-rated down to 244.

Lay out the data as follows.....

3253 – 250 = 3003 divided by 244 = 12.30

3253 + 250 = 3503 divided by 244 = 14.35

12.30 is GT/M or GT/MA. 14.35 is GT/Q or GT/QA. The car can run M, N, O, P, and Q classes in SS/GT. Weight is found by multiplying the class weight break (as found in the NHRA rulebook) times the GT horsepower and then adding 170 lbs for the driver.

Ex...GT/NA would be 12.50 times 244 = 3050 plus 170 driver = 3220 lbs. (Note: the top class GT/MA cannot go to the class break of 12.00 because the shipping weight of 3253 has already had the max of 250 subtracted. GT/M would be 3003 + 170 = 3173.)

All outer classes can use the class break when figuring the minimum scale weight.

[FireSale]

My cheat sheet.

SuperStock GT Classification Worksheet

1. SHIPPING WEIGHT

Find the shipping weight of the body you want to run in the NHRA Stock Car Classification Guide. Use the heaviest weight with the same transmission you want to run.

WEIGHT____________________________________

2. ENGINE

Find the engine you want to use in the same Guide. Find the GT Factor box at the top of the page and enter it here.

HORSEPOWER_______________________________

3. WEIGHT TO HORSEPOWER FACTOR

Divide the weight by the HP numbers you listed above. This is the Factor used to determine the GT class of your combo.

WEIGHT/HP = (_WT__________ / __HP________ = __________)

--------------------------------------------------------------------------------------
EXAMPLE 68 Mustang Coupe running a 2007 330.
(A 2008 or later 330/500 is Factory GT)

WEIGHT: 3241 (68 Coupe 428 auto)
ENGINE HP: 330/500 HP
FACTOR: 3241/500 = 6.48

NATURAL CLASS: GT/AA (Add 49 lbs to move to the top of GT/BA)
--------------------------------------------------------------------------------------

WEIGHT CHANGES

You may add or subtract up to 250 pounds to change classes in GT.
After class is determined, 170 lbs is added for “driver weight”. This is your Scale Weight. You can’t be lighter than your Scale Weight.

[Marco]

This is what I was looking for. Thank you all very much.