DLNorth, I took the 1975 850 off and put on a 1976 low hour 1150 I found. Both are the lower flywheel rated motors , the 1150 does have a fresh powerhead, I've gone through it to be confident in condition. Although the mids are the same, the lowers have different ratios and I wanted PT so in the end it was easier to swap out complete motors.
The 850 was just to clean to break up as would have been needed to leave that mid clamped on and exchange everything else required.
David, Hyperacme, good idea on the earlier brass two blade. I have an eye out for one of the 2 blade bronze "hi rake" performance props as Merc named them in the day. The standard two blade brass are not cupped so I think that makes those a non starter. I do have a 24 pitch hi rake but I think that's too steep. ( also no where near as pretty as one posted!) I have a 24 Merc elephant ear SS two blade ( also too steep for this) which testing on other hulls showed it had some bow lift, minimal torque steer and oddly it also made the motor sound different. It was however slow compared to newer three blade designs but, if I could find either of these in lower pitches those might be the ticket.
I'm hovering around 19 or 20 pitch where this is the weaker flywheel hp 1150. I think most of you here have the later prop rated 1150's in either OMC or Merc flavors, which really would compare to about 140 or so at flywheel so I have to pitch down from where you guys are.
I had not thought of a 4 blade interesting idea....not worried too much if prop is not vintage correct, I'll compromise on what's not really seen😉. The 4 blades when used on inboards are like butter.
Randy