Help on quick change gears

[hughesracing9]

I'm borrowing a set of gears from a friend that he bought off Facebook
The case is marked LP gear
The gears are both stamped J8, the small gear has "clincher" etched on it

The big gear has a concave groove cut in both sides
The teeth count is correct for a 5.30 final, but I'm weary of a mismatched set
I can only find quartermaster gears that fit a 5.30 final
LP says that part number is not there, so has anyone heard of clincher??

[hammond motorsports]

very good gear sets just not for sure if they still make gears .