Converter Question

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1971 CY Dodge Dart

1971 CY Dodge Dart

Dart Swinger
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Okay so I'm trying to determine what stall my converter is. I bought the car with the engine/transmission done and the paperwork doesn't show what it has. I read here once that if you are driving along at 10 mph and you stab the gas pedal whatever your rpm jumps up to is what it stalls at. I've tried that before and it seemed to stall at 1800 rpm but I believe stock it was around 2400 rpm. It's a 1971 Dodge Dart with a 340/727 combination. Today when I took it out it seemed to stall at 2400 rpm and spun the tires pretty good. Something it hasn't done before. Short of pulling the transmission is there a way to determine what I have?
 
Hard to check unless you have a manual valve body. With a manual valve body, you put it in 3rd, and hold the brakes, mash it to the floor for a second and see what it is. That's a pretty good indication of stall speed.
 
No manual valve body. So there's no way to know what converter is in there I guess? I was going to swap it out this Winter thinking it had an 1800 rpm stall but if it's more like 2400 rpm I'd rather leave it.
 
1971 CY Dodge Dart said:
No manual valve body. So there's no way to know what converter is in there I guess? I was going to swap it out this Winter thinking it had an 1800 rpm stall but if it's more like 2400 rpm I'd rather leave it.
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How does the car perform? I wouldn't worry about a arbitrary stall figure unless you feel like there is a issue, like lack of low end ect
 
replicaracer43 said:
How does the car perform? I wouldn't worry about a arbitrary stall figure unless you feel like there is a issue, like lack of low end ect
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It did feel like it lacked low end grunt up until today when it miraculously started leaving harder than it used to. The only thing I did was remove the floor mat which was possibly keeping the gas pedal from going all the way down.

The motor is a mostly stock 340 with less compression I believe from the factory. Also the 3.23 gears don’t help but I do a lot of highway driving.
 
I probably wouldn't go to the trouble to change the converter, for what you describe. Probably could look at the timing curve and pep her up some, cheap and easy
 
Then do a what I call a running stall test. Get the car warmed up good. Pull it out in the street. When there's no traffic of course. Get hard on the brake with your left foot. Now with the right, stab the gas to the floor while delaying VERY slightly letting your foot off the brake. You want to hold it back JUST enough to allow the converter to spin up some. You're not testing for stall speed here. You're testing for "happy factor". It SHOULD pretty much liquify the rear tires if everything's a good match. If it does, I wouldn't change anything.
 
RustyRatRod said:
Then do a what I call a running stall test. Get the car warmed up good. Pull it out in the street. When there's no traffic of course. Get hard on the brake with your left foot. Now with the right, stab the gas to the floor while delaying VERY slightly letting your foot off the brake. You want to hold it back JUST enough to allow the converter to spin up some. You're not testing for stall speed here. You're testing for "happy factor". It SHOULD pretty much liquify the rear tires if everything's a good match. If it does, I wouldn't change anything.
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Thanks, I will do some more testing on this.
 
Update

So I sent a copy of the invoice to the transmission shop that rebuilt the transmission with the part number on the invoice. Unfortunately the response I got was it’s got a converter that stalls around 1700-2000. Why that was used is beyond me.
 
Sounds like a stock converter. It’s nice for cruising, efficiency and mileage.
If you can deal with something feeling a little mushier so you can get into the power band sooner then consider a looser converter.
 
1971 CY Dodge Dart said:
Update

So I sent a copy of the invoice to the transmission shop that rebuilt the transmission with the part number on the invoice. Unfortunately the response I got was it’s got a converter that stalls around 1700-2000. Why that was used is beyond me.
Click to expand...
Stock medium stall.
 
1970/71 340's with the 727, the Factory converter stalled 2200/2400. The shop I worked at, all 340 converters were core in first.
 
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