1977 904 horsepower limits?

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Well whatever it is he replaces it and bolts it in. :). Not sure on the brand or part number but they last for me whatever it is.
 
Go to www.tcsproducts.com and look through their web page and see what is available for the 904. They and other performance automatic transmission companies will have what you need to build any 904 you want.
If it was mine: and I wasn't racing --> Raybestos waffle lined friction plates, along with new steel plates, Overhaul gasket and seal kit of course, new bands (Kevlar if you so desire), bushing kit, washer kit, roller sprag kit, TF-2 transgo shift kit, filter, output shaft bearing (it's old and got a lot of miles on it). In other words, a complete, no short cuts taken rebuild. Check and then recheck the planataries for excessive wear or sloppiness, look closely at the pump gears and replace if questionable, look at the input shaft for spline wear, replace the forward clutch diaphragm spring (prone to cracking) and look closely at the two drums for wear. Update the reverse servo piston, get the intermediate accumulator repair kit. I would think that this would/could hold up to 350/400 HP.
Now if you're racing, that opens up a whole other thing. Getting ANY transmission to live up to the racing life depends on the thickness of your wallet.
Others may disagree.


I know this isn’t but This sounds like my transmission guy. To me it’s a bunch of jibberish but he knows what he’s talking about. All my mopar stuff gets between 4 (mud truck)seconds to 9.7 (drag car) seconds of punishment every time I crank it. A junk yard was going out of business close to me and had 4 sb727s and a ton of 904s on a shelf and I have trashed most of them that I bought and some of them now are built up and it’s true the more power you want it to put down the more expensive. Like I said before the way I usually tackle this is through someone who does it a lot. In front of the trans I can do it all behind the converter is my weakness but I can give some sound advice and that is when a trans let’s go sometimes your motor will to no matter how well it’s built then your wallet can get real skinny for a bit lol
 
I'm not a transmission builder but worked for almost 30 years in the transmission parts and converter business. Most of my information comes from observing and listening to builders that I'd trust with my mothers car. Over the years I watched these builders put everyday and performance transmissions together. They all had one thing in common, they wanted to do them right. One very good builder quit the shop he was working for because the new owner wanted him to take every short cut possible, something that he would not do.
I bought a 74 Challenger back in 2002 from the original owner. It had about 32000 miles on it, and other than taking it out in the driveway once and a while to warm the juices up, it hadn't been on the road for over 20 years. Lots of oil leaks of course from sitting, and when I spoke to the guy that ended up building my trans, I told him just to do a re - seal, he said no way. "It's been sitting for a long time and it should be gone through properly". It was good advise as we found parts inside that would have probably failed sooner than later. Doing a quick re-seal wouldn't have found these issues.
The best advise I can give anyone doing their own or having someone build their transmission is:
DO IT RIGHT --- ONCE
 
I'm not a transmission builder but worked for almost 30 years in the transmission parts and converter business. Most of my information comes from observing and listening to builders that I'd trust with my mothers car. Over the years I watched these builders put everyday and performance transmissions together. They all had one thing in common, they wanted to do them right. One very good builder quit the shop he was working for because the new owner wanted him to take every short cut possible, something that he would not do.
I bought a 74 Challenger back in 2002 from the original owner. It had about 32000 miles on it, and other than taking it out in the driveway once and a while to warm the juices up, it hadn't been on the road for over 20 years. Lots of oil leaks of course from sitting, and when I spoke to the guy that ended up building my trans, I told him just to do a re - seal, he said no way. "It's been sitting for a long time and it should be gone through properly". It was good advise as we found parts inside that would have probably failed sooner than later. Doing a quick re-seal wouldn't have found these issues.
The best advise I can give anyone doing their own or having someone build their transmission is:
DO IT RIGHT --- ONCE


Dern skippy!! Once and done
 
Stock transmissions die when they are thrashed because they don't have enough line pressure. Valve body restrictions can also play a part in this. Cheap rebuilds usually mean that the bushings have not been changed and the pump gears have not been inspected or changed.
 
I'm not a trans guy as you can see from all my posts here but my old 904 lasted 2 burnouts behind my very healthy 360 before it tried to weld it self together.....

Not much help, I know just what happened to mine.....

I think I will be buying a few new parts very soon.
 
I have worked on a couple of 904s and now have a 1984 # 999 trans listed for a non lockup hi altitude 318. I pulled it apart today. It is a BRAND NEW old stock trans right from dodge, factory tag, caps and plugs still on it. 34 years of storage put a touch of rust on a couple of clutch retainers, the bottom of the oil pan and exterior pump surface , but that is it! There was enough oil in the pan to protect the valvebody.
Best part of this it has the big, wide 5 clutch drum, steel planetarys and the 2.76 gear set! So it has all the good parts needed to build a trans for my 408.
It will get new clutches that hold better, a solid kevlar 2nd gear band, forward manual valve body. The manual valve body runs high preasure all the time, and higher than max stock.
A stock trans fails due to low pressure that a stock unit is set to run, and is hog tied by the linkage system. A stock type linkage that regulates pressure would not increase the line pressure at part throttle enough because a bigger carb on a bigger motor makes a lot more Power for the first part of throttle opening than the linkage provides. MUCH more than a stock 2 bbl 318.
In 1977 the 904 was transformed into the 999 by drastically strengthening the front clutch and planetary systems. It was done to allow use behind a 360 in a heavy Fury car.
The parts for those trans are what it takes to survive behind a 408, as i understand it.
 
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