Transmission Recommended to Run Behind Built 360ci Engine in a 63 Valiant

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Hot Rod 63 Valiant

Hot Rod 63 Valiant

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From what I gather after reading quite a few threads, I will not be able to use the 904 that is currently in my 63 Valiant if I plan to run a built 360 V-8. To get an idea of the kind of motor I will be building for this car, more details are in this thread: http://www.forabodiesonly.com/mopar/showthread.php?t=198641

I assume I will need a well built 727 to put behind the motor, but what does one need to do a 727 (Or whatever transmission is recommended) so it will handle the abuse. Also, I am curious if there is anything that I could do so the push button shifter on the dash could still be functional. It's not required, but would be nice.

Thanks,
Rob
 
I'm not into automatics right now but a well built 904 will work great. They are smaller than the 727's and can be built tough enough for a stout small block. Scott (pettybludart) has one behind a powerful 408 stroker in his 66 Dart. It works good! There's a good chance he will respond later. He's probably racing today. tmm http://www.forabodiesonly.com/mopar/showthread.php?t=197010
 
Thanks Mike, it would be nice to be able to use the original 904 if I could. I know it would take a good rebuild & I'm sure some mods here & there but it make me happy as lark to be able to use it.
 
I think I would much rather throw the money out for a well built 904 that I already have than have to shove a 727 in there..... with a shoe horn I might add. lol
 
Hot Rod 63 Valiant said:
From what I gather after reading quite a few threads, I will not be able to use the 904 that is currently in my 63 Valiant if I plan to run a built 360 V-8. To get an idea of the kind of motor I will be building for this car, more details are in this thread: http://www.forabodiesonly.com/mopar/showthread.php?t=198641

I assume I will need a well built 727 to put behind the motor, but what does one need to do a 727 (Or whatever transmission is recommended) so it will handle the abuse. Also, I am curious if there is anything that I could do so the push button shifter on the dash could still be functional. It's not required, but would be nice.

Thanks,
Rob
Click to expand...

I have a superchaarged (Vortech) 360 Magnum that makes 445 rear wheel horsepower, in a 3,300-pound '72 Valiant with 9-inch slicks and a limited-dlip rear end. That 904 handles the power like it was coming from a stock slant six. Crisp shifts and no slippage... ever.

A 727 is stronger, for sure, but a well-built 904 will be more than sifficent for your needs, I think.

There were some internal changes made by the factory to strengten the 904 in 1967 or '68, so you probably should get a later model transmission, for that reason.

Good luck!
 

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Rob, is your 904 a v8 trans? The v8 and /6 are not interchangeable FYI. That being said given the choice I'll run a 904 rather than a 727 anyday. I'm running a 727 in my build only cause I got a hold of a rebuilt one for way less than rebuilding the 904 I had at the time.
727's soak up a lot of power in my experience but in factory form might have the advantage in durability. But you can build he 904 to handle more HP .
 
It's a slant 6 904 transmission. Is there any way of converting it to fit a V-8? Or do I just need to find one out of a 68-72 setup for a V-8?
 
As I understand it, if you use a 65 V8 904 with your earlier valve body, you can retain the pushbuttons. The 65 still uses the ball and trunnion joint but back in the day if they'd hold up behind a Max Wedge, it'll hold up behind a 360. Of course it would still need to be built and as Mullinax95 said, Dynamic can do it all for you.
 
65 Dartman said:
As I understand it, if you use a 65 V8 904 with your earlier valve body, you can retain the pushbuttons. The 65 still uses the ball and trunnion joint but back in the day if they'd hold up behind a Max Wedge, it'll hold up behind a 360. Of course it would still need to be built and as Mullinax95 said, Dynamic can do it all for you.
Click to expand...

The converter for a 904 (727, too, probably,) has a "button" on the front that indexes into a recess in the back of the crankshaft and it supports the shaft that the converter rides on; considerable weight.

That button was made a larger diameter in 1967 or '68, and the shaft the converter rides on was, too, so in order to run a later-model converter (and, tranny) you need this larger hole in the back of the crank..

Your crank probably already has the large hole.

On the other hand, if you want to run the smaller-buttton converter (early model for an early crank) you need to have a transmission with the smaller shaft, and an early crank, OR a bushing to make up the difference in size between the converter snout (small) and the crank hole (large.)

I have read that those bushings are available, but since your crank is a late model with the big hole, and the later transmissions are inherently stronger, why not go with the later tranny and converter, wherein everything matches?

The worst thing that can happen is that you might lose the pushbuttons, but there are lots of good floor-shifters available.

It might even be possible to adapt the pushbutton valve body to the later case; I dunno...

Good luck!!!:cheers:
 
I've got a pushbutton 904 in my 64 Barracuda with a mildly built 360 and it works very well. I put the front three main components from a '68 904 in to get the modern input shaft so I could use a more readily available converter along with the B&M flexplate to adapt the external balanced 360 to the zero balance converter. Pushbutton hotrods are cool! A well built 904 will handle a lot of power and fit into your car a lot easier.
 
Thanks for all the info & ideas guys, much appreciated. Looks like I will end up sending my 904 to a custom shop to get it modified & beefed up to work with a later model 360 engine. I'll give Dynamic converters a call to see if they can do the work or if they can recommend a good shop if they can't. I don't trust the local transmission shops we have here for something like that.
 
If your tranny is for a slant six it will not mate with a v-8. You'll need to round up a v-8 tranny.
 
grimreaper said:
If your tranny is for a slant six it will not mate with a v-8. You'll need to round up a v-8 tranny.
Click to expand...

Damm, lol, that will probably be a chore. Not sure where to even look. Wrecking yards around here don't have anymore old Mopar parts. Any suggestions besides ebay & craigslist?
 
Depends what 904 you want but it should be easy to round one up. Try posting a "parts wanted" on here to see what folks near you have. 64 or 65 with the pushbutton valve body, rear pump etc. may be a little harder to find but a 68 or later should be real easy.
 
Gonna throw you a curve ball.Try a Trans King,AMMCO.Any trans shop.Get yourself an A.T.R.A 904 manual.Cuts the B.S out.Used one on my T/H 400 build,you won't regret the investment.
 
Abodybomber said:
Gonna throw you a curve ball.Try a Trans King,AMMCO.Any trans shop.Get yourself an A.T.R.A 904 manual.Cuts the B.S out.Used one on my T/H 400 build,you won't regret the investment.
Click to expand...

Hmmm......... :-k Do elaborate when you have time, I'm always open to ideas from outside of the box.
 
Sorry,trying to make it simple...sorry.The simple way,buy a A.T.R.A book,for a 904,the professional handbook for understanding the basics.If you liked the head porting thread,wait till you read the book!
 
mullinax95 said:
Good info Bill!
Click to expand...

Thanks, Marland. I have some experience with that because our slant six has an early forged crank (small register hole,) but we wanted to use a later 904 (larger input shaft) so we had to buy a bastard converter that fit the bigger shaft , but had the smaller converter button on the front.

If I'd known, I could have had the hole in the back of the crank enlarged while the engine was dis-assembled... but, I didn't.:banghead:

I know now... LOL!:violent1:
 
The small snout converter can be used in a later engine (360 etc.) by using an adapter ring available from Pat Blais Transmissions. The other option for the earlier transmission is to swap the front three major components from a post '68 transmission to get the later input shaft. Then you have a mutlitude of torque converters available that fit the larger crank hole.
 
i run a 904 with a 520hp stroker and 518ft tq and it handles it easily but it is built to handle it and the 904 is 2 tenths quicker in the 1320 thats the same as takeing 200lbs off your car.... jimjim
 
ATSG booklet helps too.

Learn to rebuild it as they are really easy. Essentially the same as a 727, just scaled down.
 
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