1977 727 questions
#2744116
02/17/20 11:29 PM
02/17/20 11:29 PM
|
Joined: Feb 2020
Posts: 19 Winnipeg, Manitoba, Canada
'70Satellite
OP
member
|
OP
member
Joined: Feb 2020
Posts: 19
Winnipeg, Manitoba, Canada
|
Hey all. I've got lots of great feedback from my camshaft post in the engine area, and didn't realize how much cam choice and stall had to do with each other. I am still learning after all. So now, I've got this 1977 727 that I got with the same year 440. The 440 is being rebuilt, but I'm a little lost on the 727. I've been told it's a lock up transmission, and that Mopar started that in 1975 or something. The question is, if my tranny is a lock up tranny, what exactly does that mean regarding setting it up to handle 350hp, 375tq? No racing involved, just weekend cruising. I've been told a 2400 stall would work for my engine and 3.55 rear gear, with 28" tall tire. Today I was told that I would need a lock up converter and that would be almost impossible to find. So what gives? Should I just find a totally different tranny or can this tranny in fact be used for my pretty mild weekend cruiser? If I've left out any info that's required, let me know.
|
|
|
Re: 1977 727 questions
[Re: '70Satellite]
#2744201
02/18/20 10:31 AM
02/18/20 10:31 AM
|
Joined: Jan 2003
Posts: 11,994 Benton, IL.
DaveRS23
Special needs idiot
|
Special needs idiot
Joined: Jan 2003
Posts: 11,994
Benton, IL.
|
You are sure getting a lot of conflicting info. The tranny gurus should chime in here and give you accurate info on the lock-up part, but I didn't think the big blocks got it. But at any rate, you most certainly do not have to have it. A lock-up torque converter is essentially a clutch in the torque converter that engages when cruising which takes out the small percentage of slip inherent in the fluid coupling. That makes for a very efficient connection between the engine and the wheels what increases fuel efficiency and reduces a small amount of heat. Important to a daily driver and for CAFE standards, but not so much for our muscle cars.
It varies somewhat, but converter slip at cruise should be in the single digits. Not a big deal for us. I put an overdrive 518 behind my Hemi, but didn't mess with the lock-up mainly due to the limited selection of converters for my application.
You will have no problem getting a 727 to hold the power you expect to generate. Without too much effort or expense, a 727 can be built to handle nearly twice what you expect to have. They are a great tranny.
As to the converter, that choice should be determined by what you want the car to do and how you intend to drive it. It does sound like you want a fairly stock/original experience with your car. That will be no problem. Just go to one of the many competent converter builders and tell them what you want. They'll build it based on your preferences.
Master, again and still
|
|
|
Re: 1977 727 questions
[Re: '70Satellite]
#2744361
02/18/20 05:39 PM
02/18/20 05:39 PM
|
Joined: Jan 2003
Posts: 25,726 Rio Linda, CA
John_Kunkel
Too Many Posts
|
Too Many Posts
Joined: Jan 2003
Posts: 25,726
Rio Linda, CA
|
Lockup didn't arrive until '78 and, in '78, there was only one BB lockup 727; so they're pretty rare.
The INTERNET, the MISinformation superhighway
|
|
|
Re: 1977 727 questions
[Re: John_Kunkel]
#2744390
02/18/20 07:19 PM
02/18/20 07:19 PM
|
Joined: Jun 2003
Posts: 21,397 It's a dry heat
gtx6970
Too Many Posts
|
Too Many Posts
Joined: Jun 2003
Posts: 21,397
It's a dry heat
|
Lockup didn't arrive until '78 and, in '78, there was only one BB lockup 727; so they're pretty rare. I was wondering this, Ive never seen a big block 727 that had lockup. to the op, on a lockup trans the end of the input shaft where it goes in the torque conv is hollow and will have I think 3 seal rings where it seals in the front drum if you happen to have it apart
|
|
|
Re: 1977 727 questions
[Re: '70Satellite]
#2744404
02/18/20 07:52 PM
02/18/20 07:52 PM
|
Joined: Mar 2011
Posts: 3,068 Michigan
A727Tflite
master
|
master
Joined: Mar 2011
Posts: 3,068
Michigan
|
So am I to understand that the only "lock up" part of the tranny is actually in the torque converter? Or is there some other hardware in a 1977 727 TF that makes it a lock up as well. This is kind of my confusion. A guy from Mancini racing told me I needed a lock up converter to work with that tranny. You can understand my confusion. Thanks for the info. You need a lockup converter, input shaft, reaction shaft support (backside of pump), valve body and a means to control lockup. Very early lockup was purely hydraulic ( a hydraulic lockup module was added to the valve body), then it went to a solenoid controlled lockup.
|
|
|
|
|