SS/A vs. AA/S ?

[427LX]

What the difference between the two classes?  I see where a 1964 Thunderbolt can run in this AA/S and SS/A so what is the difference between car setup?

[Dumpling]

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[thatdarncat]

The NHRA classes ending with “ /S” or “ /SA” are in the Stock Eliminator category. The classes starting with “SS/ “ are in the Super Stock category. Generalizing a bunch here, but Stock Eliminator has much more restrictive rules for the engine & suspension, Super Stock allows more engine & suspension modifications, but must still be within the rules framework of the class. Just one example - Stock Eliminator is limited to no bigger than a 9” x 30” rear tire, Super Stock can use up to a 14.5” x 33” tire. For quite a few years NHRA didn’t allow the ‘64 Fairlane Thunderbolt in the Stock Eliminator category, due to it’s limited production, but a few years ago they made the change to the rules to allow it, and some other limited production vehicles, as long as the basic vehicle was legal for the class, and a few other considerations met. So the AA/S car would be Stock Eliminator category, the SS/A would be in Super Stock.

[mbrunson427]

The class I have been getting interested in is the GT class. If you see GT/ on any of the cars, it means the engine in the car is different than any stock option for that car. You could run a high riser 427 in a 95 Mustang chassis. The GT class follows the Super Stock rules/regulations. I think they require that the engine is at least the same manufacturer as the car. Can't put a Hemi in a fox body Mustang.

I think I saw a guy running a later model Ford engine in a '65 Comet, to take advantage of the modern EFI tech that the newer engine combo allows for.

[mbrunson427]

Here you go. Its a '64

https://www.youtube.com/watch?v=1NVp8B5HFmk

[mike7570]

Stockers are the best

https://www.youtube.com/watch?v=xsis4EQeDCE&t=14s

[427LX]

Somewhat confusing.  The 1964 Thunderbolt was originally built for Super/Stock but ran in A/FX until the required number of cars were built. I had always thought Stock Eliminator was for regular production cars. Now could the 1968 S/S Hemi Cudas and Darts be allowed in the AA/S stock class as well and why not? Where do the 1969 COPO Camaros fit in?

[mike7570]

Somewhat confusing.  The 1964 Thunderbolt was originally built for Super/Stock but ran in A/FX until the required number of cars were built. I had always thought Stock Eliminator was for regular production cars. Now could the 1968 S/S Hemi Cudas and Darts be allowed in the AA/S stock class as well and why not? Where do the 1969 COPO Camaros fit in?

Originally those cars couldn’t run stock, there wasn’t a AA class for them and they had too much HP to run in A because the needed weight to make the “weight break” exceeded the allowable amount.  Some made it into A but NHRA added hp when they would run under the index. At a point NHRA changed weight breaks and added AA which allowed them back in to stock. Maybe Rory can correct me if my memory is fuzzy.

[Rory428]

That sounds right, Mike. Before NHRA introduced the "AA" classes in Stock Eliminator, several years ago, the highest class was A Stock, which had a power to weight ratio of 8 pounds per advertised or factored HP. The Thunderbolts, and some other high HP lightweight combinations were below that threshold, so although they could compete in the higher Super Stocks classes, they did not "fit" into Stock. With the introduction of the newer faster classes, the Thunderbolts finally had a home in Stock Eliminator.