stock A904 converter ratings

New cam is recommending 2k stall. When looking around I came across these two options. One says light pads/Low Stall another says high stall and another still has no designation. Does anyone know what the stall is on these converters?

Furthermore the 1st two say for '77-up. Is there a difference between '68-76 & '77-up?

High Stall '77-up

Low Stall '77-up

No designation other than '68-'76