Race 727/904 build up

Engine combos have been discussed, as have suspension. I figured it was time to pick the brain of a few of our transmission gurus. So guys, how would you build a 727 or 904 for race use? Break it down into et/mph levels, if needed.

I am not a trans guru, but I have built my own for a 600 hp application. And I have torn them down after a years running and inspected things to see how they held up (twice). Also, I have done a few for friends making less power. So, my 2-cents to get things started:

1) Get a good valve body
2) Get a good valve body
3) Use a 727, they are strong as an ox

- a heavy duty front band servo strut is available from a few vendors, Superior #K031 for example.
- Sonnex makes a billet rear servo piston that doesn't crack, and resists getting cocked in the bore. #22912
- for low band apply valve bodies, I think a stronger rear servo retainer is a good idea, and shim inside the small piston spring close to solid, so the cushion spring doesn't compress.
- use the '70 and earlier front servo (not the '71 oil cushioned)
- Set the clutch pack clearances on the tight end of tolerances, especially the rear clutch
- Get some new bushings put in almost everywhere if it hasn't been done in 30 years.
- The front pump bushing (for the converter) is a mandatory replacement everytime, use the babbit ones
- A deep sump pan and filter extension is a good idea and makes the fluid level less critical
- New springs and rollers in the sprag ($2), or a new bolt-in one

See my trans page on my website for some other options:
440 Jim's web site - 727 Trans Tips

I found something I saved that I posted before:

If you are going to a trans brake, the trans must be modified for its use during the build, so now is the time to put it in. For example, drilled oil pressure relief holes in the clutch, drilled case for the solinoid wire, relocated vent, number of front clutch springs, etc.

I don't have any cook book list to give, but here is my 2-cents. A 727 can do 600 hp with very little changes. But some things are nice to have for additional piece of mind or to assure a good part.

- A good valve body (with a brake in your application)
- Check everything for wear (pump rotors, drums, ring rubbing surfaces, etc.)
- Relocate the vent with a brake (plug the front vent)
- All new bushings (just do it now, any refresh maybe not)
- All new thrust washers (cheap insurance)
- Set clutch pack clearances for the application
ex/ 0.012"-0.015" per front disc (0.060" for 5 discs)
ex/ 0.025"-0.035" rear with 4 discs
- Check sprag for wear, at a minimum new rollers and springs
- Bolt in sprag optional, but now is the time to do it
- 3.8 or 4.2 front band servo lever (see valve body instructions)
- Rigid/solid front band (IMO releases better than flex band)
- Babbit converter bushing in the trans pump housing
- Pre-'71 "solid" front servo, or shim the newer oil cushioned servo so it is solid
- Shim the rear servo so the cushion spring is almost solid
There are other "optional" mods on my web site:
http://pages.moparpages.com/440Jim/website/id4trans.html

I like the oil passage enlargement mods (ported reaction shaft support between the rings, clutch retainer holes 5/32", 1/16" oil hole to the sprag).

anyone else have anything to add?

It's not "perk", I felt it would benefit ALL members to have this info and be able to add it to the archives.

I've been doing some heavy research on street/strip racing 727 trans. 440Jim was kind enough to provide alot of information for me, thanks again Jim!
I'm am trying to gather enough information for my third trans... this one will be done correctly...lol, no more BOOM for me anyway,

I have a better understanding of the internal parts that should be used, but I'm still unsure of what types of SFI approved cases there are for the 727. I have found a case that is call an "UltraBell" and was wondering if anyone knows of this case and if it's any good. Are there any other SFI approved cases? Are there any clearance issues to be concerned with...ie; A-body application?

If the UltraBell case is a good/safe case then my last question would be concerning the starter location on the case. It appears to me in the pic that the starter mounts from the side rather than from the front....uummm clearance issue problem maybe?

Here is a picture of the case with a discription.

The Ultra-Bell and Ultra-Case combination provides tremendous strength and versatility by allowing the case to bolt to the following designs: Buick, Chevrolet, Chrysler, Ford, Oldsmobile and Pontiac engines. The combination eliminates the need for a flexplate shield and transmission shield. Furthermore, the Ford and Chrysler engines allow the starter to bolt directly to the "Ultra-Bell".
Performance benefits include:
Adjustable transmission brake release.
Improved CNC machined oil passages which increase the oil flow of the transmission brake.
Eliminates case breakage through increased aluminum in critical weak areas of the stock powerglide cases.
Less flex on the shift leaver due to increase of case material and less seal leakage.
The modulator boss has been increased drastically to eliminate cracking.
The "Ultracase" is approximately four pounds heavier than a stock powerglide case.

Mike that's a pic of the ultra case, it's for powerglides. You can use that case and the JW ultrabell to adapt it to a mopar, great for racing but I didn't think you wanted to stray from the 727 on ur street/strip car? As far as I know they don't make an aftermarket case for the 727 yet, it would be nice tho . What i'd like to hear more about is Coans new heavy duty sprag, i'd like to see some results of that thing in a no low band apply VB trans.

How bout we get CRT to put one in my trans for free and i'll try and blow it up

Hey CBK

That's why I'm asking partner, I don't know...lol
I would think that there is an SFI approved case for the 727 so I don't have to run a trans blanket or a shield.

If someone tells me that "NO" there are not any approved SFI cases for the 727, then I will start looking for information on another type of trans for my 440 that is SFI approved and does not need a trans blanket or sheild.

As far as I know there isn't, but my knowledge on trans's doesn't go very far . Your best bet would be a powerglide like the one you showed, or maybe a TH400? What's wrong with building a nice 727 and putting a CSI shield on it? I'll get ya some pics of mine tonight, and possibly of it in the car if everything goes right .

they do....

Wasnt someone makeing a new steel drum? I know aluminum drums are safer than stock but wear out and contaminate the fluid,steel would be the way to go. I would also like to see testing done with the new super roller and manual valve body without low band apply.

TCS makes a steel front drum for the 727. They advertise here too.
Link to TCS steel drum

Quote:

---

they do....

---

well , who do ???