I'm looking at getting a new Mercury Enertia prop. I've heard great things and I think it has everything my boat needs, but I'm going from a four blade to a three and I'm a little unsure of pitch. I've talked with a few prop guys and they all a close but not the same. I would like to go with the least pitched prop and add a little if i need it, but I don't know how much more pitch I can have someone bent into a prop. Any suggestions? That prop is a X7 alloy stainless.

you will need to start with the pitch of current prop you are using on the boat..mfr,hull ,model,whose drive and current displacement and hp of your engine..

It depends on what 4 blade you are running and where your rpms are now.
More than likely you will want 1" more pitch in a 3 blade vs a 4 blade to keep the same rpm.
General rule is a prop can be changed 1" of pitch up or down. Not sure if the X7 alloy is any different in that respect.

What Griff said.

You also have to take into account what dia. your 4 blade are. If you go to a 3 blade, but also go to fx. 14" dia from a 14½" dia. then the rpm diff will be even greater. I'm pretty sure that the X7 props have thinner blades than the regular alloy props, so that could make a diff too.

1" up or down. Thats what I as looking for! Thanks