727 vs 904

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sorewrist1

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If you change out a 727 to a 904 transmission can you use the same driveshaft?
I seem to remember one trans is shorter Thanks all
 
they are often the same . but no guarantees. they made several different versions for different models
 
golden boy said:
they are often the same . but no guarantees. they made several different versions for different models
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Not trying to be a jerk but your wrong. There often the same is wrong. The 727 & 904 are different lengths. There is a truck/RV 727 that is longer than the standard 727.
There is also hood differences. And then U joint size.
 
"Normal" pass car 904's are same length as a bell and A body A833 4 speed

"Normal" pass car 727's are same length as bell and B body A833 4 speed

I don't know about different length 904's never seen one

There are 1 or 2 differnt length 727's trucks motor homes etc.
 
General passenger cars.....
727's are longer and take a different yoke and torque converter. You can use the same linkage, speedometer cable, starter and NSS wire.
When going to the 904 from a 727 you'll need a longer drive shaft, 904 yoke, and 904 torque converter. All else should work just fine.
 
I don't think the kickdown linkage is the same. 727 has a longer lever on the transmission and I think the bell crank is in a different spot as well. Been awhile sense I've done that swap. But drive shaft and torque converter are not the same of sure.
 
That’s true. The levers are different on the transmissions.
I would think there already included on the trans. That has not always been the case for myself though and thus learned the hard way.
 
Engine to trans braces are the same, 904 to 727. The kickdown lever is also the same, being car specific. The A bodies, and the B Bodies 66-70 use the 3 pc bellcrank setup. E Bodies, B Bodies 71 up and C Bodies use the one pc rod setup. The 3 pc bellcrank system use the shorter kickdown lever, where as the one pc rod uses the long kickdown lever. There are slight variations in both levers. Also Dodge pickups always used the 3 pc bellcrank systems. Also the shift lever is your car specific.
For example, a 68 318 dart with a 904, swap to a 727- use your 904 kickdown lever and shift lever. Everything should be fine. If the car is a column shift, the Z bar is different between the 727 and the 904. I'm the guy that will never use a cable kickdown setup. I have boxes of stock linkages that I cut up and modify. I've probably fixed 25-30 peoples kickdown linkages with my parts. I tell the people, my setups won't be 100% factory and 95 % of the Chevy guys won't know that it's been fabricated. And they all work like they are supposed to.
 
Thanks all you guys that chimed in Lots of good information here for sure Just got the torque converter rebuilt so Ill stay with the 727 Thanks again
 
I knew there was all different types of kickdown setups. Did not know the braces were the same. Thanks for the info.
 
The length difference is all in the tail shaft. Im not sure the shift lever is different, since its in the same location. There are many different shift lever for different applications but I really think you can use the one off your existing trans.
 
Hellrats said:
The inspection plate and lower support bars are different too
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Hello. If I wanted to replace my stock A727 out of a '68 A body (Signet), I guess I would have to do some "customization" to the lower trans support. You mentioned that they are different between the two trans. When was the 904 first made? I never heard about them until a few years ago. Can they be made to handle 500+ hp.?
 
727 and 904 use the same cross member.....yes...a 904 can handle 500 hp.....
 
Thanks, '70AAR, I found out several hours ago, that the 904 was introduced in 1960. It is aluminum and there have been several versions of it since then. I take it the A904 is lighter, if I remember a post correctly.
 
I'm going to build a 371 and put it in my Signet. The Signet will go on a serious diet to shave as much weight off of it as I care to take it. I haven't been able to source any fiberglass bumpers yet.
 
Rumblefish, it is a 1968. I like the triple taillights, compared to the other Valiants with the same body style. Thanks a lot for the link to Glasstek. I'll check them out. I think I will become a Gold member, too!
 
Do most people prefer the 727 over the 904? For a street and strip build with over 500 hp, which trans would make the best choice? Either one?
 
Ether would do. The 904 has the edge in weight and less power consumed turning the wheels. If your starting with a 904, it should be the V8 variants. Look up your specific trans for what’s inside.
 
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