904 or 727 in 66 barracuda

-
searcher1990

searcher1990

Well-Known Member
Joined
Feb 20, 2015
Messages
422
Reaction score
248
Location
Oregon
I have a 66 barracuda that I am installing a slightly built 340 in. It is a 4 speed car but my left knee is now shot. I am going to swap it to an automatic so I can drive it and not have to sell it in a year or so. it is not a # matching car in any way shape or form. I will keep all 4 speed parts with car so it can be turned back if desired down the road. I am unsure if a 727 will fit in a 66 a body or not? I am not an auto guy until now and don't want to buy a trans that wont fit. What is the difference between a 904 and 727? thx for any help in this and all info is appreciated.
 
I had to pound the seam up flat against the floor to get mine to fit, 64 barracuda.
 
A built 904 is probably best suited for the earlier A. Smaller, faster, lighter, compared to the 727.
 
Sounds like a 904 is best . time to go shopping for one and all the other stuff to make it work. I think a console will look good and hide hump? thanks fellas
 
904 will fit in the A Body easier, more room around the case, and run out good too.

904

20180204_170853.jpg


727
20180620_181813.jpg


20180620_181752.jpg
 
Are you familiar with what to look for in a 904 & their differences? (i.e.: lock-up/non lock-up and later std. size converter snout & splines as opposed to early small snout?)
 
Dumb question: anybody tried a A500 trans in that body-style? My understanding is that the A500 is a A904 with overdrive (and the A518 is the 727 with overdrive).
 
J Glenn said:
Dumb question: anybody tried a A500 trans in that body-style? My understanding is that the A500 is a A904 with overdrive (and the A518 is the 727 with overdrive).
Click to expand...

The A909 (a 904 with lockup converter), the A500 (904 with a fourth gear added to the rear of the case).
Google is our friend . . . lol . .
 
brian6pac said:
Nice paint George, did you polish them first ?
Click to expand...

Degreased, Deburred high ridges with 24 grit on grinder, 80 grit on DA, 180, little hand sanding in corners.

2 Coats Gray Primer Surfacer
2 Coats Chrysler Silver Basecoat
2 Coats Clearcoat

A real pleasure to work on the cars when things are cleaned up like this, easy to keep clean.
 
Another consideration - Driveshaft.

904 should be same length as abody 4-speed w/slip yoke AND will have same slip yoke spline count.

So no changes required to drive shaft.

727 will require shortening the drive shaft ( about 4") and different slip yoke.
 
The smaller 904 case also give more room for exhaust and maintenance. A500 is 904 based but requires major modifications to transmission mount (torsion bar) cross member and floor pan to use as well as shortening of driveshaft. Biggest durability complaint I'm aware of was with the early push button shifted versions which used a smaller diameter front pump drive on the converter. Personal experience with this failure, pump drive would shear off converter, when launching my 3000# car at dragstrip at a 4500 stall speed on slicks. In normal use behind a mild built street motor I've never seen this failure even in the early 904 versions. So I don't think they are an especially "weak" transmission. My 2 cents.
 
Fredsgarage said:
Im. not. Please reference .
Click to expand...

This is some general info. Others with more internal torqueflite knowledge may offer more details.

* Late '70's or early 80's started getting lock-up converters. Input shaft splines are different so converters do not interchange.
They can be converted to take the more common converters by changing several parts, including the valve body. Lock-up transmissions have a smooth, machined tip.

* Very early 904's also have different spline input shafts and their converter has a small snout to fit early 273 crankshafts. These also do not interchange with later generations. They went to the bigger snout around '66, I believe. Someone makes a ring adapter to make the small snout fit into the bigger register on later, more common small block cranks.

* There are several "duty" levels of the 904. The best is a 999, which was found in '74 360-4 engines & some other later applications. But any "regular" V-8 904 transmissions would be suitable for your application, especially when performance oriented parts are used - i.e.: bands, clutches, valve body or shift kit, etc.

Lock-up - non lock-up trans.jpg
 
This is some veery good info here as I had not a clue on these. Thanks to all you I'm sure it will save me some $$ and time.
 
J Glenn said:
Dumb question: anybody tried a A500 trans in that body-style? My understanding is that the A500 is a A904 with overdrive (and the A518 is the 727 with overdrive).
Click to expand...

searcher1990 said:
This is some veery good info here as I had not a clue on these. Thanks to all you I'm sure it will save me some $$ and time.
Click to expand...

The A500 (42RH) is basically a 904 with an overdrive 4th, so it's a 4 speed 904.
Some had a lockup converter which connects the engine directly to the trans mechanically. (feels like being in 4th or 5th in a 4 speed or 5 speed car.) so technically 5 different speeds.
When in lockup the trans cools better because there is no converter slip friction heating up the fluid.
Also the engine to trans directly being connected means less loss of efficiency in the drivetrain, so it also helps with fuel economy on the longer drives.

Didn't see anywhere (maybe I missed it) how the car is normally driven, but just off the top I think a lockup 904 would be an easy and totally worthwhile swap behind a 340 but what do I know? :D:rolleyes:

I realize a lot of this information was already discussed, I just thought it would be nice to have it all in one place and not all be in transmission guy language.
 
904 hands down.

searcher1990 said:
I have a 66 barracuda that I am installing a slightly built 340 in. It is a 4 speed car but my left knee is now shot. I am going to swap it to an automatic so I can drive it and not have to sell it in a year or so. it is not a # matching car in any way shape or form. I will keep all 4 speed parts with car so it can be turned back if desired down the road. I am unsure if a 727 will fit in a 66 a body or not? I am not an auto guy until now and don't want to buy a trans that wont fit. What is the difference between a 904 and 727? thx for any help in this and all info is appreciated.
Click to expand...
 
67/6barracuda said:
A built 904 is probably best suited for the earlier A. Smaller, faster, lighter, compared to the 727.
Click to expand...
I would agree. Either can be built to handle the HP. 904 takes less HP to spin. if I was starting from scratch, I'd go that way
 
You must log in or register to reply here.
-

Back
Top