Building a 904 torqueflite

[jerrysant45]

Hey guys I currently own a 66 valiant that I am building. I just finished a turbo slant 6 that will be going in soon, but my transmission is leaking tons of oil, I have an extra a 904 laying around but I am trying to identify the year on it and I honestly don’t know what I should be looking to rebuild when throwing some power at it. Right now I’m just looking at clutches bands and a shift kit. Does anyone know the limits to the a 904 and how to identify the year of one? The numbers on the driver side of the oil pan are 3515804 3575 0098

 

[WV64Signet]

Look right along the side of the case where it joins the trans oil pan.

There's a set of numbers that will ID it

 

[jerrysant45]

Look right along the side of the case where it joins the trans oil pan.

There's a set of numbers that will ID it

Are those the numbers I posted those are the only ones I could find from trans case to pan

 

[moparlvr166]

1971 passenger car and truck 198/225. Question is. What year engine are you using,
Crankshaft to T/Converter coupling needs to match.

 

[GTX JOHN]

We routine run 904 to 400+ HP with little modifications
and 600+ HP with all the ProTrans Billet internal stuff.

They are one Tough little transmission!

 

[jerrysant45]

1971 passenger car and truck 198/225. Question is. What year engine are you using,
Crankshaft to T/Converter coupling needs to match.

How’d you figure that out not saying your wrong just genuinely curious the motor I’m building is a 225 out of a cuda.

 

[67Dart273]

How’d you figure that out not saying your wrong just genuinely curious the motor I’m building is a 225 out of a cuda.

The crack register for the converter changed in ??68? from smaller to larger. You can not put a late trans/ converter in an early crank, and if you use an early trans/ late engine, you need to find or make a bushing

 

[jerrysant45]

We routine run 904 to 400+ HP with little modifications
and 600+ HP with all the ProTrans Billet internal stuff.

They are one Tough little transmission!

Thank you I was wondering because we bored out the slant 6 with a hardened rotating assembly, new pistons, sent the heads out for porting and polishing and now put a Holley 4 barrel carb to a turbo in a draw through set up. I’m gonna start off with 8psi hoping for atleast 300ft/lbs maybe even more and was worried about the trans holding up. Didn’t wanna be one of those guys that puts a bunch of money into the engine just to blow a trans.

 

[moparlvr166]

What year is the engine? I used a book written by Tom Hand; it has useful information.

 

[jerrysant45]

The crack register for the converter changed in ??68? from smaller to larger. You can not put a late trans/ converter in an early crank, and if you use an early trans/ late engine, you need to find or make a bushing

Dang thank you this is my first mopar build I’m only 18 and got so much to learn it seems like a lot of people don’t build the slant 6 and just throw 318 or anything else in there do you have any recommendations on where to look or what you would do?

 

[jerrysant45]

What year is the engine? I used a book written by Tom Hand; it has useful information.

Sadly when I bought the car it wasn’t running and the guy just through me a extra 904 trans he had in the garage (his wife told him to get rid of it) he won’t anwser and I have no previous knowledge. I’m in quite the predicament sadly.

 

[WV64Signet]

How’d you figure that out not saying your wrong just genuinely curious the motor I’m building is a 225 out of a cuda.

There is an index in the back of this book which translates those numbers.

https://www.amazon.com/dp/1613253354?tag=fabo03-20

Likewise, your block casting numbers and date code stamp will provide the insight on the engine date

 

[WV64Signet]

Dang thank you this is my first mopar build I’m only 18 and got so much to learn it seems like a lot of people don’t build the slant 6 and just throw 318 or anything else in there do you have any recommendations on where to look or what you would

Going to the small block will create several other items you would have to change up. Nothing wrong starting out with the slant 6 if you're headed that way. It's a good motor

 

[jerrysant45]

Going to the small block will create several other items you would have to change up. Nothing wrong starting out with the slant 6 if you're headed that way. It's a good motor

Yea that’s what I was thinking thank you, is there anywhere you would look for those bushings or have you heard of anyone doing something like this?

 

[junkyardhero]

i cannot stress this enough: buy the Tom Hand book. it's worth every dime.

also if you don't already have a factory service manual get thee to mymopar.com and download one immediately.

a properly prepared 904 will take a criminal amount of abuse before giving up the ghost.

 

[transman]

We routine run 904 to 400+ HP with little modifications
and 600+ HP with all the ProTrans Billet internal stuff.

They are one Tough little transmission!

Lots of HP parts for the 904 are available. Not cheap, but worth the coin.

 

[transman]

Yea that’s what I was thinking thank you, is there anywhere you would look for those bushings or have you heard of anyone doing something like this?

Keep in mind not only about the 1.550" pilot on the converter, but if the transmission is an early one, the input shaft will have 18 splines, not 27 like the later transmission. If however you use the 68 and on transmission, any good converter rebuilder can remove the 1.810" pilot from the front cover and replace it with the smaller pilot if the engine is an early one. I've seen it done many times. What year Cuda did the engine come out of??

 

[WV64Signet]

Yea that’s what I was thinking thank you, is there anywhere you would look for those bushings or have you heard of anyone doing something like this?

Search function is your friend.

1965 Barracuda 904 converter bushing issue.

If it can be done, or even if it can't... there's probably a conversation that has been had on here.

 

[65 Dartman]

Dynamic Converters rebuilt my 64 LA 904 and changed the from drums and input shaft to accept a 68- later converter (which they also built for me). I can use a LA V8 or with the slant to LA transmission adapter, use a slant

 

[JDMopar]

His 904 is the later version. If he gets lucky and the 225 he has is also, he should be good to go with the converter to crank register deal. If he has an early crank with the small hole, the best thing he could do would be to find a later 225 crank to use when he builds the engine.

It's good to see a young guy taking an interest in the hobby us old gray/bald heads have enjoyed......even if he's 2 cylinders short!

Welcome to FABO @jerrysant45