I'm surprised at the responses. Tracy as usual is right on. Yall seem to forget, Mopar converters are higher stall speeds than their brand X counterparts. A stock grandma 318 converter stall speed is generally around 1500-1700. The factory high stall (which would have been behind any 340) was right around 1000 rpm more than that. That doesn't mean you're gonna get a 2500-2700 flash RPM. Many things have to be considered like vehicle weight, gear ratio, engine torque output, tire size and on and on. But the spec DuBob shows in the book up there ^^^ is dead nuts RIGHT. The 340 never had a 904 behind it, so that's comparing apples to oranges. The 727 takes more torque to drive, so there goes a few more RPM of stall. The 904 will naturally stall lower behind anything (all other things equal) since it is much lighter and has less reciprocating mass. Generally, the stock 340 A body cars would stall somewhere around 2K give or take. The B bodies a bit higher. Again though, all dependant upon which gear ratio the car had tire size.....blah blah blah.
About the OP's question. It really cannot be answered very accurately, since he left out some key ingredients. Such as, what is the engine transmission combo in? Gear ratio? Rear tire size? Vehicle weight? All of that and then some will have an effect on the final stall or lockup of the converter.
Lastly, there is really only one way to do this and get it pretty accurate and you have to have a manual valve body to do it. You need to drop it into high gear, hold your foot firmly on the brake and ease the gas pedal down until the RPM on the tach stops climbing. THERE is your stall or lockup RPM. Any other method and you leave some guess room.
