At the stall speed of a coverter you have nearly 100% slip. Most on here agree that 5-6% is good. I know at a few hunded rpm above stall the slip should be pretty high but should reduce as the rpm goes up. My question is how many rpm above stall should you see the slip approach 5%

Depending on the diameter, fin angle, stator angle and internal
clearances.........for a typical 5500 stall 8" for a SB, probably
1500+ RPM.

Thanks for the reply.
The reason I ask is that I have a 496 and flash stall at 5600 but because of my rear gear (3.55) I am going through the traps at 6300. Only being 600 to 700 rpm above stall I do not want to assume too much slip untill I try a 4.30 gear. My tach is very old but I am currently figuring about 20 percent slip.

The lower gear will help in two ways..........

1st, it will increase the RPM of the engine for the same MPH.

2nd, it will decrease the load on the converter at the same MPH.