904 vs 727

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GermzD74

GermzD74

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Couldn't find any threads on this.

I visited a wreck yard today and a topic that came up was this one. A man suggested me to keep the 904 in my car since it'll save a lot of work (not sure what work but Im guessing with linkages and length) its ligter and can handle a nice SB if rebuilt properly.

Here is a reply to a question some guy made about the same thing.

"Yes, your stock shifter, linkage, and cross member will work.

But I would question why you're replacing the 904? The 904 can actually be built to handle very high horsepower and has less internal friction than a 727, so more power goes to the rear wheels. It's also somewhat lighter than a 727.

I'd recommend building the 904 with a shift kit and bolt in sprag, add an aluminum front drum if you're making more than 500 horsepower, and it will outperform a 727 in your application."

Now if a 904 is a good option, can I use my 904 on my 67 valiant? or are the later years better? Where can I buy the stuff needed to rebuild and make it handle a small block? Money wise is it better to go with a 727?
 
stick with the 904... have some one that know what they are doing do a quailty rebuild with a shift kit in it and it will be god to go... it has to be a small block 904 if its goingh behing a small block. IIRC in the earlier ones (i forget what year it changed) the input splines were different . you want the later one is what you want for more and cheaper converter choices.
 
abodyjoe said:
stick with the 904... have some one that know what they are doing do a quailty rebuild with a shift kit in it and it will be god to go... it has to be a small block 904 if its goingh behing a small block. IIRC in the earlier ones (i forget what year it changed) the input splines were different . you want the later one is what you want for more and cheaper converter choices.
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Thanks for your input! Btw...I also mentioned to the guy my interest in a 4 speed converstion...I would really like the extra fun plus value in my car...but herd its a hassle and its gonna be hard to find the needed parts, somewhat costly too...but I told him I am good researchin (if I know what im looking for which i dont haha other than the 833, bellhousing, shifter with linkages, and thats it haha)
 
904 is all you need. Parts are readily available..There are a couple guys in our club running them in thier drag cars and they have no reliability problems.

I would have kept mine, but stumbled on a cheap 518....and I really wanted overdrive.
 
superdart said:
904 is all you need. Parts are readily available..There are a couple guys in our club running them in thier drag cars and they have no reliability problems.

I would have kept mine, but stumbled on a cheap 518....and I really wanted overdrive.
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is the 518 an overdrive automatic tranny? Is that better on gas? How hard was it to put that in?

BTW...Im reading there is also a A-500

A-510 being a 727 with OD and a A-500 a 904 with OD

Can a 904 be rebuilt with an overdrive gear in it?
 
The 904 version with OD is an A500/42RH, there is an electronic version but you don't want that one.

The 727 version with OD is an A518/46RH, same thing on the electronic version.

The A500/42RH will have a lock up convertor which is not desireable for performance applications. But will work in street/mild strip applications.

You can get the A518 in both lock up and non-lock up versions. I have a non-lock up version I took out of a '92 B350 van.

The 904/A500/42RH is pletty capable in a small block application.


Chuck
 
but herd its a hassle and its gonna be hard to find the needed parts, somewhat costly too...but I told him I am good researchin (if I know what im looking for which i dont haha other than the 833, bellhousing, shifter with linkages, and thats it haha)
Click to expand...


brewers and passon performance will sell you an entire 4 speed set up... the parts aren't too hard to find.. some you can get new. an a-body 23 spline 4 speed isn't all that hard to find either.. seen them from $100-$300
 
You can also use th o.d. tranny from a F body. Then you have the fun of a stick and the over drive.
 
340mopar said:
The 904 version with OD is an A500/42RH, there is an electronic version but you don't want that one.

The 727 version with OD is an A518/46RH, same thing on the electronic version.

The A500/42RH will have a lock up convertor which is not desireable for performance applications. But will work in street/mild strip applications.

You can get the A518 in both lock up and non-lock up versions. I have a non-lock up version I took out of a '92 B350 van.

The 904/A500/42RH is pletty capable in a small block application.


Chuck
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Isnt some tunnel work needed to install these into an A-Body?
 
I have heard there is a lot of work and then I have heard there is minimal work required. I haven't done one yet so I don't exactly know what is required in an A-body.


Chuck
 
AdamR said:
You can also use th o.d. tranny from a F body. Then you have the fun of a stick and the over drive.
Click to expand...

Finding one as a donor would be perfect, I have all the time in the world to find one...not in a rush since I have a poor idea of what I'm doing (haha)
 
I saw some pictures "somewhere" of a 518 going into an early A. They had to cut the crossmember of the unibody that goes over the tranny. Kinda gives me the willies, since that is the crossmember that the t-bars mount to. I guess it could be boxed back in and reinforced on the sides and be sturdy enough, but that's guesswork and I don't think I would risk it. The Gear Vendors unit looks best to me. If I remember correctly, it still needs tunnel modification, but not in a highly stressed area. The there's that GM 4 speed auto conversion if you can stand to do that to your MOPAR. But I'm thinking that one needs tunnel mods at the firewall, 'cause the tranny is FAT.

BC
 
My 518 went in with no floorboard modifications whatsoever.

The crossmember WAS cut out and replaced with a custom brace that welded to the floorboard, and a new transmission mount was fabricated to fit the new trans and tie the crossmembers from underneath. The car also has 2" box subframe connectors. The chassis feels super solid now.

Currently I am running it as a 3spd because I'm still running a 2.45 final drive. My next project is a rear axle build using 3.55s and a new style 29 spline Limited Slip.

Once the axle is done I'll wire up the OD to function as designed (no toggle switch except to override the circuit at the track).
 
Superdart,

It sounds like you reinforced the cut out crossmember as well as I can imagine. I'm not a welder or fabricator - yet. I did find the ad for 700raptor.com and followed this link: http://www.transmissioncenter.net/SwapInformation.htm

Seems to be pretty similar to what you mention, re switching. I'm always looking to learn more about improving my rides, both current and in planning.

Do you have any photos of the reinforcing job on that upper crossmember? This seems to be a better alternative than the Gear Vendors unit and probably less expensive. The fabrication of the crossmembers is what interests me the most, since the torsion bars tie in there. But if your fabrication restores or maybe exceeds the factory's production method then it's WAY cool! Since you're just up I-35 from me, maybe I'll have you do the fab work on my 64ragtop.

BC
 
Yep, I plan on purchasing their kickdown/switch kit for my trans when the time comes.

I didn't personally do the work on my trans swap. It was done by a fellow Mopar Club member, Mike Miller. He is the owner/operator of Miller Performance Automotive here in Haltom City (just outside Ft. Worth).

http://www.millerperformance.net/

I have no pictures of the brace work itself, but I can check with Mike to see if he took some before he bolted the transmission in. He's built more than a few very nice race cars, so I have faith in his chassis ability.

Some of the pictures I DO have are located in this thread. I have some more, but I need to post them.

http://www.forabodiesonly.com/mopar/showthread.php?t=27244

Don't mind the new floorpan. Apparently the drain for the A/C was bad once upon a time and it rotted out the passenger floorpan.:wack:

Basicly it involved:

- Cut down/fabricate a new tie-in across the tunnel
- Fabricate a new trans crossmember
- Trans mount is a GM type
- Driveshaft was replaced (Usually, they just need to be cut down, but mine was a double walled, rubber bushed type, so it had to go).
- Linkages all work on new trans. (I have column shift, but will be converted to floor shift).
-Adapter fittings for cooler lines. AODs use 3/8 lines, not 5/16. Mine was just converted to all 3/8 line, running it up the subrframe and away from the headers and engine.
 
I'm planning on going to an OD A-833 setup in my Duster. Specifically I'm going to try to find a cast-iron non-OD A-833 case (either 23-spline or 18-spline) and buy the Hemi Overdrive conversion kit from Passon Performance. I'm also going to run a hydraulic clutch setup most likely from Keisler. That's a few years down the road though, when I also get a good 8-1/4" rear end and build up a nice 360 to swap in. I'm taking a welding class now in school also, so I think I'll be able to do all the tunnel mods myself.
 
If you are going to an 833, are there any mods necessary? A-bodies came with 833s, so I wouldn't think any chassis mods would be needed.
 
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