Had gear issue in a #4 upper. Had someone, certified MERC Speedmaster, repair a drive that had 1.40:1 that gear is NLA instead a 1.330 was used. Was told there would only be a 35 rpm difference between the 2 with the same props and set up. I don't believe this to be true. I need some expert data on this with facts.

I have enlightened myself. Spoke with a past Lake X EXPERT. More like 200 rpms or more.