727 vs 904?

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coalman

coalman

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Which of the above is the better of the two, have not purchased an automatic Mopar in some time? Thanks
 
It would be best to provide some context to your question as 'better' is quite generic. Will the transmission be used in a daily driver, for a quarter mile car or for auto crossing?
 
Trans parts and converters all being equal, a 904 will be about .15 faster in the 1/4 mile, has a 2.71 (or 2.74?) low gear option and is less prone to grenading.

A 727 is naturally stronger and will likely be good for most applications.

Both started appearing with lock-up converters in the late '70's, which is not the best choice for performance builds. Many parts, including converters, can't be "mixed". Either all lock-up or non-lock-up. But the lock up parts can be swapped out as a set.
 
And that .15 in the 1/4 is for race (or being raced) vehicles. In the street, you'll never know it.
It is also a little lighter. Which helps.

Some people here like to split hairs and ridicule for the use of a 727.
 
rumblefish360 said:
and that .15 in the 1/4 is for race (or being raced) vehicles. In the street, you'll never know it.
It is also a little lighter. Which helps.

Some people here like to split hairs and ridicule for the use of a 727.
Click to expand...

^^^^^^^^^^this^^^^^^^^^^^
 
The factory put the 727 behind the HP 340 for a reason.

Today though if weight is an issue and you need the extra tenth in the quarter than 904 Can be built to work
 
Well, growing up I remember this was never even a question - the 727 was the only way to go - now, "they" have done so much with the 904 that it is a point of fairly strong debate, and from what I have heard and read, it's for good reason. I've never used anything but a 727 and have yet to have a transmission fail - I have been accused of some "spirited" driving in my day.. dats all.
 
I got into a really huge argument over this on a facebook post a while back.

Yes A727's is stronger but heavier with more parasitic loss. But the gap between 727 vs. 904 has been narrower nowadays. The A904 can be easily built to be quite strong.
A904 (or A998/999) have less parasitic loss and some are equipped with wide ratio gear sets.
With A727 you're stuck with the 2.45-1.45-1 gear set.
A904 series came with the 2.45-1.45-1 or 2.74-1.54-1 gear sets.

I just did a non-lockup conversion on my A999 this last summer.
I was just surprised how simple these torqueflites are to work on, even a knuckle-dragger like myself can do it.

http://www.hemmings.com/hmn/stories/2014/01/01/hmn_feature26.html
 
I was just surprised how simple these torqueflites are to work on, even a knuckle-dragger like myself can do it
Click to expand...

Baha ha ha ha ha ha ha ha.....
 
I was just wondering, if modifying a 904 with only a shift kit, does that make it any "stronger", if you know what I mean?
 
I would say whichever you find a deal on, or one you know to be good, that's your choice. I ran a 904 behind a "bolt-on" performance 340 for years. I did have a tranny guy build it though, with a Cheetah manual reverse pattern VB. Had a lot of fun w/that setup too.
 
I think it just depends on what you have. If you already have a good torque converter and driveshaft for a 727 would it be worth going to a 904? If you were starting from scratch and had a 904 I would build it.
 
Been running a 904 behind my 416 and 360 never and issue and that tranny gets beat on every race season..wouldn't waste MY money on a 727...
 
904 hold very well behind a small block 340 or 360, if you are burning them up then find someone else to rebuild them for you...

I have been doing my own for 10 yrs now..and I am no expert....I have had two 904 that had problems ..both were my screw up...rolled a lip seal...and forgot a spacer...LOL...

Refreshing one now that has been his service since 1992.....We have 3 cars that race and all use transbrake......
 
stroked340 said:
Been running a 904 behind my 416 and 360 never and issue and that tranny gets beat on every race season..wouldn't waste MY money on a 727...
Click to expand...

For racing purposes, I agree that a 904 should be used. However, if a 727 is all you got or for non racing use, I don't see a reason a good working trans should be swapped out.
 
here is my thoughts on the subject..

if i bought a car and it is a running/driving car then i'll reluctantly keep the 727.

if i don't have either trans in the car i'm putting a 904 in it every time.

if i have a 727 laying around i'm selling it and building a 904 and installing the 904.
 
Better in which regard? There are pros/cons to either. But in reality, either one would get the job done. Been through both, and seriously, either will work for most applications.

But the all out race person would probably lean towards the easy choice, of which one nets faster ETs.

If you had both in front of you and you had to decide which one to put in your car, either one works.
 
dibbons said:
I was just wondering, if modifying a 904 with only a shift kit, does that make it any "stronger", if you know what I mean?
Click to expand...

When I first got a bone stock '72 340 Challenger, I ran the heck out of it. Almost got banned from driving it to school because of the burnouts, fast driving, etc. at school and the neighborhood. I went through 3 727's in a year. After my transmission guy finally put a shift kit in, it lasted.

A 727 is "physically" stronger than a 904, but a shift kit will help any trans live longer because it minimizes clutch/band slippage and heat. I was abusing mine to the point that it needed help over stock. My current race car has a 904 and they last for years.
 
From the discussion it seems that you have to get the 904 "built" in order for it to perform. Or does it outdo the 727 when both are in factory stock form?
 
abodyjoe said:
here is my thoughts on the subject..

if i bought a car and it is a running/driving car then i'll reluctantly keep the 727.

if i don't have either trans in the car i'm putting a 904 in it every time.

if i have a 727 laying around i'm selling it and building a 904 and installing the 904.
Click to expand...

What he said:D:D
 
Neither. Go with a GM 200R4 (2004R whichever you prefer to call it), lighter than both and you gain an overdrive gear so you can use 4.10 gears out back and not drive yourself insane while on the freeway. Plus the 200R4 is all hydralic! And yes this trannies can live behind high hp/TQ motors just fine.
 
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