904 vs 727?

-
80fbody

80fbody

Well-Known Member
Joined
Apr 9, 2011
Messages
710
Reaction score
133
Location
Belchertown, MA
Is there a "rule of thumb" concerning how much would be picked up by going with a 904 instead of a 727? It would only be behind a 400hp smallblock in a dart. Likely a 12 sec. package (for now).

I've got to build a tranny either way as most of my stuff is 4 speed right now.
 
I have seen a couple folks pull the heavy 727 out for a strong built 904, back in the late 1990'es the worlds fastest door slam'er had a 904 trans in it and ran under 10 seconds on the Memphis Motor sports 1/4 mile track in a 71 dart I believe
My choice would be a 904, lighter and as strong for these light race cars JMO.
 
80fbody said:
Is there a "rule of thumb" concerning how much would be picked up by going with a 904 instead of a 727? It would only be behind a 400hp smallblock in a dart. Likely a 12 sec. package (for now).

I've got to build a tranny either way as most of my stuff is 4 speed right now.
Click to expand...

one to two tenths in the quarter.

have had the same 904 in my dart since 05. there is nothing exotic in it. it has many low 12 second runs on it and a bunch of very hard street mileage..
 
80fbody said:
Is there a "rule of thumb" concerning how much would be picked up by going with a 904 instead of a 727? It would only be behind a 400hp smallblock in a dart. Likely a 12 sec. package (for now).

I've got to build a tranny either way as most of my stuff is 4 speed right now.
Click to expand...

I'm running a 727 but in a A body the 904 fits better, can be build just as tuff and a 727, and is faster then 727.

Really the 904 is better in every way.....EXCEPT the 904 crack TQ hubs!
This has inproved A LOT in the past few years,......but they still crack, after a lot of use.
 
Lots of my friends are using the 904 in their stock/superstock cars running in the 10-11 second range. No problems with the 904.Mine has hundreds of runs and has been behind 2 engines and still going strong.Thats over a ten year span.
 
I'm running a basically stock 904 with about 200 11 second runs and 50 low 10's. 727's are heavy and have issues not experienced with the 904. The CSR shield fits without modding the tunnel. Car weighs 2900
 
Wow. Glad to hear the success stories. I was leaning towards the 904 as I believe I have a 998 from a 81 J-body that could donate some parts if it's a lock-up. I haven't separated it from the 318 yet.
 
80fbody said:
Wow. Glad to hear the success stories. I was leaning towards the 904 as I believe I have a 998 from a 81 J-body that could donate some parts if it's a lock-up. I haven't separated it from the 318 yet.
Click to expand...

that may even have the low first gear.
 
80fbody said:
Is there a "rule of thumb" concerning how much would be picked up by going with a 904 instead of a 727? It would only be behind a 400hp smallblock in a dart. Likely a 12 sec. package (for now).

I've got to build a tranny either way as most of my stuff is 4 speed right now.
Click to expand...


Back in the '70's Chrysler and Turbo Action did a series of tests between a 904 and 727. The conclusion was that if both transmissions and corresponding converters are built to the same level, the 904 will be approx. .15 faster than a 727. This was behind small block SS cars of that day, which aren't near as fast as the same ones today Not sure if the did the test using Stockers also. But it wasn't legal to put a 904 behing an engine that came with a 727 from the factory back then.

I have a 904 in mine built by JW transmissions with a 2.71 low gear and the usual good bands, clutches, manual valve body, etc. Nothing "trick". I have run 11.22 at 3,540 lbs. without any problems. Regular servicing and a deep pan help as well as a good fluid. JW says to keep using whatever fuid I'm using in the trans about my Amsoil Supershift when I do bring it in to freshen every several years.
 
I wouldn't touch a lock up converter with a 10ft pole. Every one of them I've had have gone bad sooner than non lock up. Be it chevy or dodge. The one in my Cordoba now, locks and un locks randomly as it chooses. Go non lock up for more longevity
 
I agree with DobaDaddy. It is possible to swap out certain parts to convert a lock-up trans to a non-lock-up. Same with putting the 2.71 gear into a non-lock-up trans because very few, if any, non-lock-up transmissions had that low gear.

Converters don't interchange either so a non-lock-up combo opens up your options.
 
I'm going to take a shot & build one myself. I enjoy the process these days. going to get a 904 & see if that other 998 has the low gears.

Anyone have a quick "partslist" that I need to aquire for the build. Will grab a master kit just need to know if there are certain drums, planetaries, pumps, etc that I need to source before starting.
 
Locomotion said:
I agree with DobaDaddy. It is possible to swap out certain parts to convert a lock-up trans to a non-lock-up. Same with putting the 2.71 gear into a non-lock-up trans because very few, if any, non-lock-up transmissions had that low gear.

Converters don't interchange either so a non-lock-up combo opens up your options.
Click to expand...

Really?!
 
You must log in or register to reply here.
-

Back
Top