KR valve rotators

I am trying to find a pair of the valve rotators that were used in the KR's.
Anybody have any or know of an aftermarket part number. Sifton came up with these to take care of exhaust valve distortion. They were suppose to be 6 cyl. International truck engine rotators but I don't know which engine.
Mike

Get to be buddies with your locaql NAPA parts counterman,Napa has the best selection valves on the planet,if you have any luck,how about posting it? BREWSKI