how much horsepower can the 904 take?

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jhaas63

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Would a 360 crate motor be too much for the 904 transmission?

I have the 8.75 rear end and the 904 tranny....maybe one day ill drop a 360/380 and take out the 318 in my dart.
 
a properly built 904 will easily handle the crate motor....

buy good kit with alto red disc...kolene steels...replace the single wound spring in the front clutch pac with a 24 spring kit.....use a 4.2 kickdown lever on the street.....also...get a TransGo TF-2 kit or buy a good valve body...

I currently have 3 904s in use for drag racing and they have several season on them with no problems... I am sure they are seeing more the 380 HP....
 
Ditto to Cudda's statement above. I have the 360/380 crate with a 904 (hard parts installed) in a 73 Duster, reverse manual valve body.
100 Shot NOS; never used

Tranny shop advised could easliy do 500 HP.
 
I also run a 904 in my 66 Dart race car(410c.i/904/Dana 60).I had some internals changed(lower 1st gear,redd belts,blue clutches,changed out the drum)These 904,s will handle a crate engine no problem.Good luck.
 
yup.. a quality build by someone that knows what they are doing and using quality parts a 904 will handle a lot of power. more then that crate motor can ever dream of making...
 
Transmission Durability and Longevity are both the results of keeping the fluid below 200* through whatever abuse it is put through.....Fluid reaches 230-250-280 and the transmissions life will be measured in minutes/seconds.

A more robust cooler than just the Engine Coolant Radiator is needed when power levels exceed 400 crank horsepower.

A stock 904 could handle a MP Crate 360 no problem.
 
A friend of mine has a 904 behind a 625 HP 340 in his race car, seems to do fine. It is however built beyond stock specs.

For the 360 it should be fine, unless you plan on racing it, using a trans brake etc, I would run with it.
 
TCS Products in Langely BC sells the 24 spring return module combined with a billet steel or alum drum { get the steel one for street use } as a package that when coupled with their deluxe race rebuild kit { Red frictions ,Kevlar front band etc...}and a good valve body makes a 904 that they run in their 1400hp Pro comp Eliminator car ,if you make more power than that then you should probably go in a different direction .
 
cannucky said:
TCS Products in Langely BC sells the 24 spring return module combined with a billet steel or alum drum { get the steel one for street use } as a package that when coupled with their deluxe race rebuild kit { Red frictions ,Kevlar front band etc...}and a good valve body makes a 904 that they run in their 1400hp Pro comp Eliminator car ,if you make more power than that then you should probably go in a different direction .
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TCS products..got a link?
 
As everyone has said, a properly built 904 will take that 360 without an issue. For example, there are guys running 904's behind big blocks "with an adaptor" in super stock classes. The 904 is a much lighter, and less restrictive trans compared to the 727.
 
dodge freak said:
if its just an stock rebuild, it won't last so long, well depends how you drive. The 904 does need some beefing up to live a long time
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Define "beefing up"......

the difference in cost between alto disc and kolene steels might be 40 dollars...and you dont have to replace the single wound spring....only need if you are going to rev it up over 6500 rpm...
 
I had a rebuilt 904 last me 15 months and it was wiped out, got it rebuilt again and got 8 months. Then I found a different trans shop, lol

Straight factory they were not so beefie, 6000--6500 isn't no biggie from a SBM, if the motor can rev and has some power and you drive it hard all the time, well good luck if its all stock or a cheap rebuild
 
BadAss71 said:
As everyone has said, a properly built 904 will take that 360 without an issue. For example, there are guys running 904's behind big blocks "with an adaptor" in super stock classes. The 904 is a much lighter, and less restrictive trans compared to the 727.
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Hmm adaptor is new to me. I know that many racers use the 727 case with 904 internals to save weight..
 
You really don't need a fancy or expensive front drum in a 904. They don't detonate like the 727 units do because they are smaller in diameter.
 
crackedback said:
You really don't need a fancy or expensive front drum in a 904. They don't detonate like the 727 units do because they are smaller in diameter.
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I agree it's not needed for the strength of the drum but I bought mine for the relocated snap ring groove that allows for 5 of the thicker red frictions { they claim it will hold up to six frictions but they must mean the thinner stock type } and that it was sold as a kit with the 24 spring return module and the piston designed for the module
 
cannucky said:
I agree it's not needed for the strength of the drum but I bought mine for the relocated snap ring groove that allows for 5 of the thicker red frictions { they claim it will hold up to six frictions but they must mean the thinner stock type } and that it was sold as a kit with the 24 spring return module and the piston designed for the module
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wow, some nice parts but that kit is 575 bucks!!

http://www.tcsproducts.com/products/product/12/


looks nice though....i bet over kill. lol

........i like overkill.....lol
 
abodyjoe said:
yup.. a quality build by someone that knows what they are doing and using quality parts a 904 will handle a lot of power. more then that crate motor can ever dream of making...
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Yes yes yes. Joe is bang on! In fact with some expensive mods,a 904 can be used behind a big block with reliability at the track.
 
Rick Allison at A & A Trans carries parts to build a A-904 or he can build one for you. He does top notch work, he has been build trans for the likes of Big Daddy for a long time... He is a true Mopar guy too boot...


http://www.aandatrans.com/
 
mopardude318 said:
wow, some nice parts but that kit is 575 bucks!!

http://www.tcsproducts.com/products/product/12/


looks nice though....i bet over kill. lol

........i like overkill.....lol
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Yes they are expensive but I'm looking to build it once and not have to worry about the 525/529 it is behind hurting it ever , I too like overkill ,price out the full race rebuild kit and their 10 inch converters and you'll see what it costs to build overkill up here in the great white north
 
I know this is an older posting, with that being said, I am trying to decide whether to keep my 904 automatic or convert to an 883 manual. My 64 Dart Gt has the unique pushbutton variety. I went to the various vender links in this posting and noticed that the performance kits indicate 1966 and up. So, I have to ask, is there a performance kit for my 1964 904?
 
The one I have from Performance Automatic is rated at 400 hp. It just has a shift kit and probably some better material but it's not really "built up".
 
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