Re: 1974 Johnson 85hp 3 or 4 blade
Very basically a 3 blade has good all around performance with good top end.
A 4 blade has better over all low to mid range performance and handling with slightly less top end.
A ss prop will usually outperform an al prop though the difference could be as low as a few tenths to a few mph.
A ss will usually cost 3 times or more than an al prop.Al props are more delicate in contact with the bottom but cost less to repair
Ss hold up better in contact with sand or mud but cost more to repair.
