904 into a 727 ???

Was on Class Racer.com and reading a comment or complaint from some of the Ford and Chevy stock class racers. they were upset that the Mopars were allowed to install 904 parts into the 727 Case and it is supposed to be worth a 10th of a second behind a big block.
HOW??? can you install 904 parts int a 727? Do you have to do a bunch of machine work and spacing or sleeves to the 727 Case? I know the 904 stuff is smaller and lighter than the 727 stuff and i am pretty sure it has a lower first gear ratio than the 727.
Anyone in here done this conversion?

I've heard of this (on here) but have no idea on how it works

Pro Trans does it, maybe A&A too. Not exactly cheap.

Chevy guys have been using T-200 stuff and the Ford guys have used C-4's, they have no room to [censored].

$1800, actually same length inside, they use the 727 front pump

The case is modified, internals are mostly all custom. Not something that most folks should try to do. Better to buy a used unit if you don't want to pay for a new one. There's a reason they are expensive.

As mentioned above ProTrans in Lancaster Calf is the premier builder of the lightweight trannys. If your competitive in stock you probably have their parts. A&A is probably strong in this area also, just I'm not familiar with their work on the lightweight internals. But a .1 is an average number for the light weight internals Protrans parts, and many of them close to .15

went through a buddy of mines stocker.... ubercool! This is one of Dave's older units... and you might be surprised where 904 guts have been made to fit

and you might be surprised where 904 guts have been made to fit smile


...haven't they put them in th350's?

It seems to me that some of the west coast 428 Ford Mustang guys where the first non Mopar guys to get 904 parts in their race trannies, many years ago
Dave offers many different straight cut gear ratio for them along with the lightweight low drag race parts also

I seem to remember, tech only had to have them (non mopar cars) select park. Car rolls, you're busted.

ok i'm not trying to hijack this thread, but since there's people who know a bit about this, whats a Pro Flight? I thought this was a mix of 727 & 904 parts??

That is my understanding.

I don't know where the $1,800 came from above but the Protrans stuff sells used north of $4,000. New with custom ratios, way up there.

Bill

I talked to two long time stock racers, Joseph Teuton and John Irving about this mod, they told me that was the price of just parts, not the whole trans. Maybe they get good deals. You would be supprized how close the guts are, I was going to make one myself till I found out the price, but I will call to make sure, I'm sure price reflects what bells and whistles you get too.

I believe the Pro flight is in a custom case and it is a three speed tranny with all lightweight and low drag parts made for drag racing only, mostly Comp Eliminator cars of all brands, 4 cylinder to V8 motors. Dave can be reached by phone at 661-940-7400 PST, not sure if he has a web site or not now
He builds custom drag race trannys with his parts in stock cases for cars that require that also

We did this way back in the mid 80's. They are a lot nicer pieces now.

Yes based off the T Flight, those little (250-277) cu inch small blocks needed that low gear in their heavy (3000 lb and up) rides. Those cars are fun to watch, hold your ears though.

Have a friend that has a late model COPO Camaro (LS engine and a supercharger) factory racer that replaced the original TH400 with a Turbo 350 that has 904 guts. When money's no object, racers use whatever works best.

When you are serious about class racing $10k to gain .05 is nothing.

What I've read from a trans builder who does this conversion is that the lifespan of the 904 guts is far shorter for big block cars. He said something like if you could go 200 passes on a 727 behind a competitive big block he wouldn't expect the 904 guts to make it to 100. Definitely something for the racers willing to spend whatever for small improvements even with more frequent maintenance.

I had one of the AH guys tell me 6 to 10 runs, but that was a few years ago.

I had one of the AH guys tell me 6 to 10 runs, but that was a few years ago. [/quote] High HP, very fast heads up class cars are not easy to maintain or keep going faster than the others in the same class

Interesting thoughts. I knew Roy Johnson used a 904 in his SS cars way back in 70's but never knew why.
Thanks for all of the input.
Jerry

Proflite transmissions run modified 904 internals in a 904 case.

They typically run a modified AMC 727 case (the bell housing is smaller) with an adaptor plate. The adaptor plate also helps in the use of GM convertors (they're taller and more plentiful). To allow this the 727 pump is modified, a custom stator support and input shaft is used. Dave also relocates the front band's adjustment point in the case as well.

TCS also offers replacement parts nowadays. My understanding is that Pro Trans does all the machining for the A1 Proflites as well.

Protrans also do other styles of race transmissions as well.

My buddie paid 5,500 for his 12 years ago, they are more now,and then you need the convertor. I'm hoping to find a good deal on some used ones, I need a pushbutton and the later for my two cars.

I have 3 of them and they are an easy .15 behind a good bigblock, I turned my street 69 6 pack into a stocker and when i replaced the trans from a well built 727 to a protrans I picked up .17 which part was due to a better convertor. Dave and Darren Smith are great to work with and if you need a quick turn around that is no problem. As far as longevity I have put well over 200 passes on my Max Wedge Stocker with only frequent oil changes. Are they pricey yes.

Max Weg