Transmission Adapters

[Ken Parkman]

With all this discussion about transmissions, and the fact I have a SBC pattern 904 case I'd like to sell, I went back and looked through the old rulebooks (missing a bunch) to understand how it has changed for both stick and auto.

- in 1988 both stick and auto were required to have same year make and model as the car.
- aftermarket stick transmissions allowed in 1989
- any model automatic from the same manufacturer with the same number of speeds allowed in 1991. Adapters prohibited
- OD gear not required and redrilling to adapt prohibited comments added sometime between 95 and 97
- NHRA accepted adapters permitted sometime between 98 and 2000
- sometime between 2010 and 2020 3 speed automatics allowed.

Interesting that aftermarket (stick) transmissions have been allowed for 36 years and it has been 34 years since a stock automatic has been required. For a few years it did specifically have rules that would say the transmission must bolt up. Now almost any transmission can be used, and with proflites the components are not from the same manufacturer anyhow.

It's also interesting how much wording about shifting and other things has been added.

So my SBC 904 case has no market and I think that Supra is no different transmission wise than any other stocker. And I think it is great to get a newer Stock Eliminator running in the conventional classes.