904 trans

h i have a 3550 lbs indy headed small block 580 hp going to give her 200 shot ,904 is reco stock box with trans brake vb full manual 1.55 60 ft will this handle the gas of the line?

We have been running 904's several years, in both our cars, 3000 lb. Dart avg., 1.34 60' time transbrake, in a bracket race mode with lots of passes, with nothing more than clutch wear. Our Cuda broke an output shaft once in the middle of a wheelstand, but it was 3700 lbs and 1.40 60' times footbrake, but your dealing with 30 year old parts and your putting 2-3 times more torque to it than the chrysler engineers ever dreamed.

My Demon w/904, 3175 pounds on the footbrake with 650HP 474CI R3 W9 Small Block broke the output shaft on a launch. Never had a problem until I put a 3.55 gear (28" tall tires) in the rearend and that put too much load on the trans.

thank for the info sounds like the chances are small that it might break ,so i will give it ago ,will be racing on the 19 th so i will let use know how it goes.

BTT

Who else here has experience going fast with a 904?

how fast is fast? i ran 9.51 with 1.40 short time 2500lbs car leaving 6000rpm on 2-step 27psi of boost.

Light weight tube chassis car, low 9's, 145 MPH, 1.23 60. Had a Griner brake. Never broke it, but you have to do some maintenance. Super Stock Hemi cars use 904 components in a 727 case. It can be done, but you have to use the right stuff. Don't expect a $500 trans to stay in the car all year.

If it has aluminiun planitaries in it, the splines on it wont last too long. I've broke every piece of the drive line in mine.(since the new converter)
I will also say if you have a converter that slips a lot it will help the trans live..

One of my coustomers is running an 85 short bed fullsize pup that I built a pretty strong 340 with E-Brock heads that runs 12.30s. no problems reported with the 904 trans. he has also put a little no2 through the motor. He also runs an 8.25 rear (4.30 gears) also holding up.