I would assume triangle pattern since three are used, correct?
J
I would say that three in a triangular pattern are "typical" (meaning most common and most seen). However, in my 55 plus years of working on Fords, I have seen 1, 2, 3 and even 5 used on a drum. I'll bet there were some with four also, I have just never run across one. My guess is that while the normal was most likely three, the amount used was a function of how many the Assembly Line worker had in his hand at the time. If he had grabbed more than three from the bin, rather than just throwing extras on the floor, or more appropriately putting them back in the bin or saving for the next one down the line, he just installed it (them). Just a guess, but likely.
Bob