toddo........starter bendix drive must be SQUEEKY CLEAN. I use spray BRAKE cleaner.
2nd thing, yer starter must be GROUNDED. Remove the 8" bolts and pull the starter out about 1/2". Now WIRE BRUSH the H3LL outta the gap. Now re-install the 8" bolts. Simple, eh?
Would it surprize you to learn that Ford spec'd 30wt DETERGENT oil in 1939??? Synthetic oil is also highly detergent. .........oily Dell