727 Stock converter differences, performance,towing,mileage ??

[rustytoolss]

Got a question about the Stock 727 (wide ring and narrow ring) torque converters. I see about a 200 rpm difference in the stall speeds. How much of a performance change does that make ? What about how it would effect towing and even fuel mileage.

 

[Curiousyellow71]

If you are comparing a oem10 3/4" to a oem 11 3/4"...I think there is more then 200 rpm difference more like 500-600. But...It really depends on what is in front of it and what gear and tire size you have out back.
I would prefer the wide ring gear(10 3/4" stalls) w 3.23, some of them stall around 2200 or more.
Most of the (oem)narrow ring gears (11 3/4") stall only to 1600-1800, which can be a disadvantage getting the car moving and I would only consider with 2.76s on a cruiser. But..my interest is in performance! . If it's a big old c body I might go w the lower stall.

 

[Dave6T4]

Chrysler put the 10 3/4" converters behind the 383 HP engines and the 426 Hemi. However, they never put the smaller converter behind any 440, using the 11 3/4" piece instead. They must have felt the 440 had enough low end torque that it did not need any help.

 

[transman]

Got a question about the Stock 727 (wide ring and narrow ring) torque converters. I see about a 200 rpm difference in the stall speeds. How much of a performance change does that make ? What about how it would effect towing and even fuel mileage.

What engine do you have, and what year? And what will you be using the car for?

 

[rustytoolss]

What engine do you have, and what year? And what will you be using the car for?

A 1962 Fury wagon, 318 Polysphere engine ,3.23 gears, and 27" tall tires.. just a weekend cruiser..no plans to race. Those days are behind me

 

[Dave6T4]

I would use the higher stall 10 3/4" converter, but likely hard to find for early 19 spline input shaft. Stall speed is a variable thing, based on engine power. I think a 318 would stall at the lower end of the converter rating. With a heavier car like your wagon, the engine could use some help to get it moving, like letting it rev up a little more on launch. With 3.23 gears, you would be running around 2400-2500 rpm. at 60 mph. cruise. The converter stall would be all in at that speed, so little effect on gas mileage.

 

[rustytoolss]

From what I've found, the car should weigh 3600-3650, as for the 19 spline thing. I have the parts to update to 24 spline system. So if I update the splines in the trans, I would need to get a converter (reason for asking my question)

 

[Dave6T4]

O.K. You should try and get a converter that is rated around 2200-2400 rpm. This would be about 600 rpm. more than the stock 11 3/4" one was. This is about what a 383 RoadRunner 10 3/4" one was. I can remember when you could still buy these at NAPA or Car Quest for about $150!
I think in real life, your wagon will weigh more than that, unless you did some serious lightening. I had a 3-seat '67 Coronet wagon with 440 and 4-speed that went 4250 lbs. My big block '64 Polara 500 convertible was at 4000 lbs.

 

[rustytoolss]

O.K. You should try and get a converter that is rated around 2200-2400 rpm. This would be about 600 rpm. more than the stock 11 3/4" one was. This is about what a 383 RoadRunner 10 3/4" one was. I can remember when you could still buy these at NAPA or Car Quest for about $150!
I think in real life, your wagon will weigh more than that, unless you did some serious lightening. I had a 3-seat '67 Coronet wagon with 440 and 4-speed that went 4250 lbs. My big block '64 Polara 500 convertible was at 4000 lbs.

I'm sure you are correct about the weight being more.

 

[transman]

A 1962 Fury wagon, 318 Polysphere engine ,3.23 gears, and 27" tall tires.. just a weekend cruiser..no plans to race. Those days are behind me

View attachment 1581620

Nice ride. What year is the transmission? As it is the one that came with the car back in 1962, then the converter it came with with will be a 12" (aka as a 11 3/4") narrow ring gear, 19 splines, an no weights. It was rated as a medium stall, and from the information I have, it stalled between 1900-2200 rpm. It is the only (other than the Hemi Converter) that is listed for the 727 of your vintage (1962-1966) no matter what engine is in front of it, that I have in my converter catalog. It ran fine for many years with the factory supplied drive train, and really, for what you are planning to use the wagon for, I really can't see much sense in changing anything. Get your original converter rebuilt. I'm sure there must be a converter rebuilder in your area.

Others have mentioned contacting various auto parts outlets. I'm not knocking these stores, but the people that work there usually have a very limited amount of knowledge about automatic transmissions and torque converters. JMHO and don't let price be your guide.

Have fun, and that's going to be one nice ride when you've got it finished.

 

[transman]

One company that has been mentioned on other web sites as being an excellent place to go to is Precision Converters in Bryan, Ohio.

 

[rustytoolss]

Nice ride. What year is the transmission? As it is the one that came with the car back in 1962, then the converter it came with with will be a 12" (aka as a 11 3/4") narrow ring gear, 19 splines, an no weights. It was rated as a medium stall, and from the information I have, it stalled between 1900-2200 rpm. It is the only (other than the Hemi Converter) that is listed for the 727 of your vintage (1962-1966) no matter what engine is in front of it, that I have in my converter catalog. It ran fine for many years with the factory supplied drive train, and really, for what you are planning to use the wagon for, I really can't see much sense in changing anything. Get your original converter rebuilt. I'm sure there must be a converter rebuilder in your area.

Others have mentioned contacting various auto parts outlets. I'm not knocking these stores, but the people that work there usually have a very limited amount of knowledge about automatic transmissions and torque converters. JMHO and don't let price be your guide.

Have fun, and that's going to be one nice ride when you've got it finished.

Thanks, I've also been looking into doing the PTKD update. I do have a 1971 727 with PTKD that I can use for parts (PTKD & 24 spline stuff) My trans is a 1962 pushbutton. Thanks for all the help.

 

[Runcharger]

I've swapped them before and I didn't notice any earth shattering difference. I never got a smaller one to stall higher than 2000 either. I think other than a big C-body with tall gears I would use the smaller one given the choice.

 

[Dave6T4]

Thanks, I've also been looking into doing the PTKD update. I do have a 1971 727 with PTKD that I can use for parts (PTKD & 24 spline stuff) My trans is a 1962 pushbutton. Thanks for all the help.

None of the PTKD stuff off the '71 valve body will transfer to your push button valve body.

 

[transman]

I've swapped them before and I didn't notice any earth shattering difference. I never got a smaller one to stall higher than 2000 either. I think other than a big C-body with tall gears I would use the smaller one given the choice.

340 converter stall rated 2200/2400, and having been the owner of the 71 Duster(attached photo) I bought new in 71, I can confirm this to be about right. The stall speed on some small 360 converters 2000/2200.

 

[dvw]

I have used 340 (10 3/4 high stall) as well. Depending on torque input they are normally over 2200. I've pushed them to 2600 behing big power applications.
Doug