Outdrive gear ratios

I have a question concerning d

I have a question concerning differences between omc and merc outdrive ratios. I have an 86 Four Winns 215 Santara cuddy with a 4.3 205hp mercruiser alpha 1 and run a 19 pitch stainless prop for best overall performance. It came factory with a 21 pitch aluminum and struggled getting on plane under a load. I am looking at buying a 1993 Four winns 215 sundowner with a 5.8 EFI OMC. It has i believe a factory 19 pitch aluminum prop on it now. So I guess I am wondering why a motor with 35 more horsepower has the same size prop and can I use my merc stainless prop on the OMC? I appreciate any insight you can provide!

"You have to remember, the &#3

"You have to remember, the "factory" does not install the props. In most cases that I am aware of the boat shop that sells the boat puts whatever prop on they deam fit for that boat. From what I have witnessed in the past it's a lot boy that don't know squat what should be on it that installs it."

"Ok, I thought the factory rec

"Ok, I thought the factory recommended which prop was installed. I hope to get the 93 on the water within the next few weeks. It hasn't been on the water in about 5 years and I am going to change the oil and outdrive oil before i try it out. I have been told it will run about 50 mph with the prop it has, but not sure what the rpms are at WOT. Is there a way to fit a Merc alpha 1 prop to an OMC? I would hate to spend the money on another SS prop if I can use the one I have!"