340 with a 904-1

[brotow]

Ok here's my dilemma, years back I bought a 340 6 pack engine, trans from radiator to drive shaft.  Getting ready to install when the engine is back from the re-builder. I have just found out the transmission is a 1970 a-904-1 number x3410637a.  This came out of a 1970 challenger that the owner was going to go hemi. The 340 I believe was a 1972. Is it possible to beef up this transmission to handle the 340? If so how could I tell.  I dropped the pan and it is spotless my guess recently rebuilt.  Here is the link to some pictures.

http://s1131.photobucket.com/user/brotow1/library/1970%20challenger%20transmission%20a%20904%20-1?sort=3&page=1

[blown motor]

I have a stout 340 ahead of a 904. Two years ago second gear went out and I had the tranny rebuilt. We put in a mild shift kit and it has been flawless. I've done a few passes at the track. I love coming out of town at about 30-35 and flooring it. The tranny drops from drive to first and puts you back in the seat pretty good. Since the rebuild it just wants to go. 

[RzeroB]

For the longest time I believed that the 904 was inferior to the 727. Then I began to notice that a lot of racers were running 904's behind some pretty stout motors. Apparently the 904 can more than hold it's own. There are a number of threads on the 727 vs 904 question here on C-C and over on Moparts. So unless you happened to have an extra 727 laying around the shop, I would not hesitate to set that 904 up and put it behind your 340. 

[brotow]

That is very encouraging. Thank you for the good news. Is there a way without tearing into the transmission to see if it has been "modified"?  And I do have a 727 from a 74 chall 360 less than 80k,I think?  But the 904 was supposedly   behind this 340 in the previous owners car.  Although he could not tell me if any "work" was done the transmission.  I guess a shift kit HAS to go in it.

[Chryco Psycho]

I would recommend installing a Trans Go shift kit for sure , & turning up the pressure , makes sure the kickdown linkage is set up correctly & run it , it will live .

[vinb]

Nothing wrong with a 904 , will last if done right .
Use a good cooler and a deep pan also.
It's a lot lighter and quicker ET's too..

[HemiOrange70]

also have a stout 340 and a 904 with a shift kit. No problems whatsoever.

[BIGSHCLUNK]

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