I am using a 4.3 V6 stall on my 5.0--is there a way to figuyre out what the stall speed is now?

thanks

 

step on the brake with left foot mash gas with right foot watch tach, when the car dies, or about dies that is your stall speed

 

Your car won't "die" It will simply not increase rpm any longer and most likely start to spin the tires. Just do what he said and hold the brake down with your left foot and give it as much gas as you can until the tires break loose all while watching the tach. If it starts to break em loose at 1700, then your stall speed is prolly 1600-1650 or so.