All converters are "stall converters". When someone talks specifically about a "stall converter" what they usually mean is that the stall point on the converter is higher than stock.
Ok, that said, what is "stall"?
Stall is the point at which the converter engages. Stock is low enough so that you always get some pull on the trans. A higher stall point means that you can rev the engine up to just under that point for a launch, and when the light turns green nail it the rest of the way. The trans will then engage and off you go with more torque than you would from a stock converter.
If you are serious about your launches you would have your engine dynoed and then order a converter with the stall point right at your max torque number.
Generally called a "high stall converter". It's a hotrod version of the stock torque converter in an automatic transmission. You won't really need one unless your engine is making serious power AND you're putting in regular time on the local dragstrip.
If you want a description of a torque converter, it was explained to me years ago as being like two fans. Take two electric box fans (like grandma uses instead of air conditioning) and put them face to face. Turn one on. The second fan will spin ALMOST as fast as the fan that's on. This is basically what's going on inside the torque converter, only with trans fluid instead of air. Instead of being plugged into the wall, the first fan is powered by your engine. Because the second "fan"can never quite match the speed of the first one, you lose some power compared to a manual trans and clutch (and some mileage).
The factory low stall speed converter gives you nice and smooth power on the street. With a radical high stall aftermarket converter you can rev up to almost 2000 rpm before the car even starts to move. If your car spends more than half it's driving time on the track, this is great. If it's a car you drive regularly, you'll get fed up with it really fast.
There's really a lot more to this, but that's probably more than you wanted to know already. : )
Hmmm... thanks for the explaination. This 67 coupe with a 400hp Cleveland that I might buy has a 3000rpm stall converter. I'm going to be driving this car on the street a lot... so I guess I should take that thing out. Is there such a thing as a stall converter that I can turn on and off? Off for the street and on for the track?
Can't turn it on and off the stall is set by changing the physical shape of the vanes on the impeller. I have a 2500 stall and it is a little annoying driving around especially at low speeds, but I am getting used to it. You want to make sure that the stall speed is lower than your cruising rpm or you will generate a lot of heat in the tranny fluid.
Not stupid...at very worst, ignorant...we were all there once *G* Looks like you learned alot already.
I'm going to be driving this car on the street a lot... so I guess I should take that thing out. Is there such a thing as a stall converter that I can turn on and off?
IMO, leave the converter in there, especially if the engine is a 4V (large port) Cleveland. You should have a 3.50-up rear gear for this combo, which will be fine for combination street/track driving with a 10" converter (likely what you will have). Be sure the app has an auxilliary external trans fluid cooler.
I've run 4.8K stall 8" converters on the street and, practically speaking, they're as normal to drive as stock converters, except you can leave the stoplight in high gear without any problems..*G* The race car currently has a converter similar to yours in it and is emminently driveable (once it's off the trailer, I drive it everywhere, even to get a hot dog and soda)...only time you would notice the higher stall is when briskly accelerating or power-braking the car (known as stalling the converter) on the starting line. I usually leave the line at about 2800 to leave a little flash room (converter flashes to 3200)...
If Pat says it should work, sounds like you just need to drive it and see if it suits you. You can always change the converter later on.
I admit I'm kinda biased because had to drive a car for a time that had an inappropriately high stall converter in a stockish drivetrain. It made me grit my teeth driving in normal traffic.