When shopping for the spiral coiled roll pins, for FE distributor I'd stay with the 1/8 in diameter pin. The drive gear boss is 3/4 in OD. but a little pin hanging out probably never hurt anything. So I went with 7/8 in. long, so beveled ends would be outside the drive gear boss. Zoro .com has different brands and materials. I like the 420 stainless, different double shear loads, I saw 1400 lbs. and 2000 lbs. and remember the pin should be ok but may need to break under extreme circumstances. it's a fail safe and the different brands have different quantities in a package , some are 25, 50, and 100. they have quite a list
Drilling a larger hole makes the distributor shaft thinner outside the hole. I did forget to not rev until engine
oil was warmed up one time and broke the original split spring roll pin. The engine just quit. was not real hard to fix. No real damage. remember the pictures of Brent's
oil pump locking up and it twisted the hex drive shaft into ornamental iron. Did you see his pictures of his engine bearings? that was a crutch engine , but.