Maximum HP in 904 Transmission With the following parts:

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360tripleblack7

360tripleblack7

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Hi,

I have a 1977 Brazilian Dodge Charger...

My question is: What is the maximum of my HP 904 transmission survives?

I did a rebuild of the transmission with the following parts:

TCI Rebuild Kit: 129000
Boss Hog Converter: 3200 stall
Mopar Performance Flexplate SFI aproved

I have a 360 engine with + - 450HP. With 4.27 gear and Hoosier Slick Tires 26x10x15.

My 904 Transmission will survive??

Thanks...
 
You need some servo parts. What did you use for bands? Do you have a good cooler?

Has it got a shift kit at all?
 
If you shift over 5500 I give it a year before 2nd and 3rd gears are a problem.
 
I saw a dart run a 10.38 the other day with a small block and a 904 and he has been running it for 4 years. 904's are no punks if they are build right.
 
There is a stiffer int band apply strut, billet servo pistons and go solid bands and the better clutches and plates.

I would also use the larger plantaries and a 5 stack direct drum with a 4.2 lever.
 
I have using the same 904 since 1993 with a transbrake, it has been rebuilt once in 2004 when the ring gear broke and took out the rear spraq.

On the rebuilt i used red alto clutches and kolene steels, the front clutch has been modified to carry 5 disc...I use keval bands ...a 5.0 band apply lever,,,'
the front clutch pac also has the 24 spring kit instead of the large wound spring...
and i am using a Transzact Pro brake I bought in 1993...

So you guys Who SAY they wont work are correct....

Also my 71 Dart 360 with eddy heads has a 904 with stock clutchs and steels...but again modified to carry 5 disc...and same bands...same 24 spring kit...5.0 lever...and Tranzact Pro brake...It has 4 seasons of racing on it...

both trans use the aluminum plantaries .....they are 904s not the 999

the rear servo in both trans are the Sonax replacement servo which i think cost about 12 dollars....not a high dollar billet item..

So that 904 does not work either...please ship any unwanted 904 to me...

69 barracuda runs in 10.70s ...and the dart ran 11.06 in MATS In VEGAs...
 
70aars trans sounds a lot like my 904. I haven't been running it for as long as 70aarcuda, but so far, zero issues. I love it.

I've got the A&A brake, low gear set, good bands, etc etc.

Don't know if I'm making 450 horsepower, but it will be mid-11s soon.
 
belmateo said:
in other words 904's are not that good when you have decent power in front of them?
Click to expand...

That statement couldn't be further from the truth...a 904 built properly can handle just about anything in front of it,mine has handled a 520 h.p. stroker and is currently in front of my 406 horse 360 shifting by the way at 6200 rpms for 4 seasons now..:-D:-D
 
70aarcuda said:
I have using the same 904 since 1993 with a transbrake, it has been rebuilt once in 2004 when the ring gear broke and took out the rear spraq.

On the rebuilt i used red alto clutches and kolene steels, the front clutch has been modified to carry 5 disc...I use keval bands ...a 5.0 band apply lever,,,'
the front clutch pac also has the 24 spring kit instead of the large wound spring...
and i am using a Transzact Pro brake I bought in 1993...

So you guys Who SAY they wont work are correct....

Also my 71 Dart 360 with eddy heads has a 904 with stock clutchs and steels...but again modified to carry 5 disc...and same bands...same 24 spring kit...5.0 lever...and Tranzact Pro brake...It has 4 seasons of racing on it...

both trans use the aluminum plantaries .....they are 904s not the 999

the rear servo in both trans are the Sonax replacement servo which i think cost about 12 dollars....not a high dollar billet item..

So that 904 does not work either...please ship any unwanted 904 to me...

69 barracuda runs in 10.70s ...and the dart ran 11.06 in MATS In VEGAs...
Click to expand...

Amen brother, I couldn't have said it better. You take all the 904s west of the Missippi and I'll take all of um east. Once again, I bring up Bucky Hess. He used to run the 904 in his Super Stock '68 HEMI Cuda. That car was well in excess of 800 HP. Course, it had a bunch more done to it than the OP is talking about, still they can be made to withstand boocoos of power with the right parts. To the OP....I agree with whomever recommended a good cooler. THAT will be the life of it. With the mods you mentioned it will be fine at that HP level. Also, along with the servos mentioned, you want to upgrade the kickdown band actuating arm as well. They can distort under severe stress. Mopar Performance makes a fine replacement, on the cheap.

Oh and to 70aarcuda.....how come you're moddin direct drums for five clutches? The A-500 comes with a 5 clutch direct drum and will fall right in the 904......unless you're usin somethin billet or aluminum? You can also get the 4 disc forward drum on the cheap from wittrans. check out their site. Great prices. https://www.wittrans.com/default.aspx
 
I didn't say they were junk. I said with nothign but a valve body and convertor they won't last. Which is true. The only changes I'd make are the upgraded frictions and the billet forward clutch retainer which upgrades the clutch return spring to the 727 type. The single biggest issue it that single wound return spring. High rpms cause it to unwind and lose tension, causing overlap on 2-3. Also, by changing the retainer to billet, you lose the possibility of explosion should the sprague get broken.
 
moper said:
I didn't say they were junk. I said with nothign but a valve body and convertor they won't last. Which is true. The only changes I'd make are the upgraded frictions and the billet forward clutch retainer which upgrades the clutch return spring to the 727 type. The single biggest issue it that single wound return spring. High rpms cause it to unwind and lose tension, causing overlap on 2-3. Also, by changing the retainer to billet, you lose the possibility of explosion should the sprague get broken.
Click to expand...

Hush up. Yeah you said they were junk and your word is LAW. Now, everybody east of the Missippi holler at me so I can come get your 904s. They're crap and you don't want um. You heard it hear first. LMAO
 
lol... yeah. Law... right LOL...
I gave away 9 727 cores a couple years ago. I couldnt give away the 904s so they got recycled. But, they have their uses... I'll be running one in my '65.
 
moper said:
lol... yeah. Law... right LOL...
I gave away 9 727 cores a couple years ago. I couldnt give away the 904s so they got recycled. But, they have their uses... I'll be running one in my '65.
Click to expand...

Can you be more specific about that retainer? Maybe a part number or where to get it? That's actually something I've never added. Since I'm probably gonna use this 999, I'd like to make it as bulletproof as possible. Thanks.
 
Gotta agree with moper...stock type build 904 won't last. Build it with the right stuff and it works great and will last. Chris from Andrews Racing Transmissions is a great source for info and parts. He knows what he is talking about.
 
StrokerScamp said:
Can you be more specific about that retainer? Maybe a part number or where to get it? That's actually something I've never added. Since I'm probably gonna use this 999, I'd like to make it as bulletproof as possible. Thanks.
Click to expand...

A&A has them. I can't find it on their website, but that's where i got mine.
 
66dartman said:
Gotta agree with moper...stock type build 904 won't last. Build it with the right stuff and it works great and will last. Chris from Andrews Racing Transmissions is a great source for info and parts. He knows what he is talking about.
Click to expand...
I got great advise from Chris Andrews and handed it over to my builder.The 904 is doing fine behind my 410(around 500hp) running 11.20,s in a 66 Dart.People frown upon the 904,s,but as said if built right can perform well.:cheers:
 
Just got off the phone with Andrew Racing, nice guys, we chit chatted about my stock rebuild 904 with a TA RMVB as to how much HP it'll hold, told him i was alittle concerned about spraying it with 100 shot, he said a stock 904 willl hold up to 600hp, Yep i said 600hp, they do it all the time, the only weak area at this point is in the spline shearing off, so he said 400-450hp NO problem, i'm good to go.
 
I vote for a sticky from Chris Andrews Racing,on how to build the 904 for a small block running anywhere from 400-600hp.Mine is working great from his advise.
 
I'd be interested in seeing any 904 with a Cheeta launch with 600hp... Well, more than a few times anyway. Cheetas are not low band apply. I'm not with Andrews on that one...
 
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