So the car I bought has 3.73 gears and a 3000 non lock up stall. It was a drag car and I only plan to drive it and not race so want to back to a lock up style convertor. The car also has a manual valve body and b&m shifter. I will be taking it to a transmission mechanic soon to have a standard oem valve body installed with a transgo shift kit so I can still downshift whenever I feel like doing it manually.

My first question, will a convertor lock up below stall speed? My engine is a 383 and the cam is mild from how it sounds, you can tell it's not a factory cam, but doesn't have a crazy lope to it or anything. I am thinking of going 2.73 gears since I do a lot of highway driving. So I was thinking a 2200-2500 stall with lock up would be good.

Second question, how does lock up work? Is it controlled electronically? Asking because the transmission in the car was built by Art Carr back in the 90's and I'm unsure if anything related to lock up control was removed.

 

The lockup is controlled by the ECM and there is an electric solonoid within the transmission that controls the flow of transmission fluid to the lockup clutch in the torque converter. The stall speed of the converter and the lockup are separate functions and not dependent on each other. And yes, a converter can be locked below stall speed, depending on what the ECM is telling it to do. With a high stall converter, I would want to change the parameters in the PROM chip to delay when the torque converter locks to avoid an abupt lockup. Still, with a 3,000RPM stall converter, that doesn't mean that the converter does nothing below 3,000RPM. Under light load, it will start transferring power much lower than its stall speed, but it will slip more when under a heavier load until it reaches its stall speed. And, that 3,000RPM stall speed could be higher or lower depending on how much power the engine makes, traction, etc.

In any case, if you are going to be street driving it, I would agree with getting rid of the 3,000 stall non-lockup converter and going with a lower stall RPM lockup converter. Converting the transmission back to full automatic with a shift kit also makes sense, but what you may run into is that the transmission may be missing some of those components. If your transmission guy knows these transmissions well enough, he should be able to source what is needed and put everything back.

3.73's with overdrive and a lockup converter are not a bad combo. The engine would be turning about 3,000RPM at 80mph and as long as your exhaust isn't too loud, that's fine. 3.42's or even 3.23's are probably a little better for mostly highway, but I would probably just leave the 3.73's, at least for now. I would definitely not go all the way down to 2.73's. It would be a dog with those gears.

 

Id get a lockup thats still 3000 ish stall. Go 3.08-3.23’s if you want less gear so you dont have to change the carrier, if its a 10 bolt with 3.73’s he probably put in a 3 series carrier unless they bought special gears. If its a 3 series carrier, i dont think you can get 2.73’s. Maybe 3.08’s, I think those are 3 series still Else 3.23 is fantastic overall gear

 

The rear is a GM 12 bolt from a car with c-clip eliminators and a brute strength locker I was told. It was built by a well known local racer so I don't think he would lie, but can't find any information on a brute strength locker lol. But I will take your advice and go down to just 3.08.

 

Thanks for the reply, that is what I wanted to know. Guess I will need to call the transmission shop and make sure they will be able to put the trans back together properly. What stall would you recommend for a 383 mini ram setup with a mildish cam? You think like a 2000-2200 would be fine?