Different gear ratios?

[76Red18]

Motor- 99 Johnson 150
I had to replace my lower unit last summer due to the repeated unsuccessful attempts at removing my froze in propshaft bearing carrier to replace bad bearings & seals. I tried to run a 19 pitch prop with that lower unit, but it made the motor run to tight so I put the 17 pitch prop back on and stowed the 19 for a spare. The only noticeable difference in the replacement unit was a 50-75 rpm increase(chalked up the rpm increase to the new bearings) and the white paint. I have the charcoal color scheme. I spun the hub on my 17 yesturday, so I put the 19 on till I re-hub the 17. The motor seems to handle the prop with no problems now. Are all OMC lower unit the same ratio or did I get a lower geared unit? I don't see any specs on ratios in my Seloc manual. Anyone out there knows the answer to this, feel free to respond. thanks, Richard