Transmission Adapters

[Mark Yacavone]

From the NHRA 2025 rule book, Under Stock :
" NHRA-accepted adapter plates permitted."

Anyone know where to find the listing ?
Asking for....myself.

[Stan Weiss]

Mark,
I don't have an answer for you, but that line goes back to a min of the 2017 Rule book.


Stan

[Ken Parkman]

The rule goes back to at least the 2000 rule book, so it's been there 25 years.

[SSDiv6]

Originally Posted by Mark Yacavone

From the NHRA 2025 rule book, Under Stock :
" NHRA-accepted adapter plates permitted."

Anyone know where to find the listing ?
Asking for....myself.

Once upon a time, I was told that the Quicktime bellhousings qualified under the rule, but never confirmed it. Prior to the adquisition of Quicktime by Holley, you could basically put any transmission, either stick or auto, on any engine. After the acquisition by Holley, they did away with the slow movers, however, they still have a good selection available.

https://www.holley.com/brands/quick_.../bellhousings/

[Mark Yacavone]

Thanks for the research, guys

The quote is from the automatic section though.

Can anyone go back to where any transmission from same manufacturer allowed?
Did it ever say it must bolt to the engine, or was that just understood?

[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.

[rsalemi]

Originally Posted by 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.

I long ago sold a SBC 904 case to an AMC 4 cyl guy who had a cracked case for $65 (IRC) but I think that market has dried up!!!

[Cglrcng]

Yac they should be on the NHRA Accepted Products List (if there are any currently accepted), NHRAracer.com on left, under TECH heading, Accepted Products List...Scrolled the list contents and only found Stk/SS Accepted bellhousings 3 there and all GM and all were JW Transmission and all on Pg 54. No heading there for Accepted Adapters so a call to the tech department may be in order.

Or, call JW Transmission, tell them what you want to (adapt or matchup), and they certainly know how to get it added to the list.

[Rory McNeil]

Since it appears that a Toyota is allowed to use a GM automatic transmission, because supposedly, at some point some BMWs had GM transmissions, I wonder now if Fords will be allowed to use an adapter for a Turbo 200, since in the early 50s, Lincolns were available with a GM Hydramatic . Or is such a thing only allowed on vehicles that don`t exist in the Classification Guide?

[west coast]

Rory the way I see how the Toyota got a gm trans. Ford should be able to also. Ford owned jaguar for several years, jaguar's did use gm transmission for several years. This is not different then what was just approved by nhra. Ford should be able to use any GM trans, have adapters made and have them approved or bellhousing for the 200.