The other day my mind was wandering as I was shopping for a new converter and I came across a question in my mind that I feel needs a solid answer. To the best of my knowledge, the purpose of the stall is to allow the engine to rev more freely until it is in it's optimal power range for the purpose of the motor.
In the case of a stout 440 where it will make a significant amount of torque say 500lb ft from the 2500 rpm range and up, what is the benefit of having a 3500 plus stall in the same motor? If a big cammed 440 is making over 500lb ft of power around 2500 rpm but increases it's torque through say 5000 rpm and max rpm is 6500. Said engine with a stall speed that is at 3800 rpm per the cam grinder recommendation. In this scenario, are you not wasting the torque the engine is producing below that 3800 rpm point? I guess in short, why use a high stall converter if your engine produces usable power at a lower RPM range?

Is it being wasted? Sure, but the associated lack of engine speed would mechanically negate anything you are trying to gain. It is the torque value + engine speed that is going to accelerate the car.

We all know torque over time is what gets work done. With higher engine speeds the work is being done in a shorter time, thus, improved acceleration.

Depending on the design of the converter, the other benefit of the higher stall in many cases is higher STR.

Stall Torque Ratio.

For max acceleration you want to spend as much time in the rpm range of max average horsepower.

You and I both know the answer is what your trying to do is what are you trying to do with this converter first
Street, street and strip or race only?

Converters are sold by stall speed because that's what most folks think they understand but, like Transman said, it's all about the stall ratio.

Here is a link to an explanation. web site

That high torque 440 with a 2600 stall converter will only be able to deliver the actual hp being made. 500 ft lbs torque only makes 250 hp at 2600 rpm. At 4000 rpm the 500 ft lbs has climbed to 400 hp. If the motor makes 500 hp at 5200 rpm, and the motor will still make 500 hp at 6200 rpm you have the full 500 hp average, minus efficiency loss, if you have a 5200 stall converter, average power delivered will be highest. Stall torque ratio and overall efficiency can skew the actual best stall speed.

Yes that is correct but, trying to figure out where money is best spent... Like you mentioned, some parts (stall speeds) will be more specific or efficient to a specific application. It's always a compromise, if I frequently drive my car on city or hwy streets, it probably would not be wise to choose a 4k converter. If the car is driven more street than race/strip maybe I could get away with a 2800 stall... the compromise between the two would be a 3k-3500k converter as that is in my case the cruise rpm

My guess is a tight ten inch converter should get you reasonable lockup yet stall 3000 or so.

I had a custom built 10 inch converter built off of my dyno sheets (612 HP at 5500 RPM and 644 Ft. Lbs. at 4500 RPM) for my old street and strip Duster, it would foot stall to 2300 RPM before sliding the front tires through the staging beams at the races, it would flash stall in first gear around 4200 RPM. I was happy with it until I broke it and swap in a Turbo Action 8 inch SS/AH converter I had taken in trade and never used, that converter would foot stall over 3300 RPM and flash stall to 5200 RPM, it was way easier to drive on the street and at the track
It pick my car up .2+ ET and 2.+ MPH in the eight mile, which really surprised me
My message is buy the best one you can get, call around to the better converter companies and see what they suggest, I've used several 8 inch converters on the street and for racing also