1977 727 questions

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.

Shouldn't be any reason you couldn't use that behind your combo. It's a good stout trans and you are going for mild horsepower.

post a pic of the input shaft , that will tell if it is a lock up .

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.

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.

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

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.

Thanks all. As usual, your help us much appreciated. I'm away working for a bit. I'll look at my tranny when I get home and now that I know what to look for, it gives me a better path forward. Really looking forward to having my Petty Blue '70 running around with a big block instead of the old 318.

A car that good looking really does need a big block.

I agree, that's a nice looking ride. Love the Petty Blue.

Thanks guys. 6 years of work in my unheated garage, which means only actually working on it about 10 weeks a year. Just myself and a buddy. As far as exterior goes, the only thing I'm considering is some sort of black on the hood to break up the blue. I am not trying to clone anything though. Mind you, the Satellite as far as I know was always a solid color, and it does appear really stock the way it is.

I wouldn't change the paint at all. It looks good the way it is. I think blacking out the hood would mess up the clean look you alreadyy have.