when calculating top speed with various prop calculators(rbbi,bam marine) if you lab finish your prop do you still use the original pitch number before it was lab finished ? i know the rpms will be different before and after the lab finishing.

Lab Finishing is only thining the prop unless you tell them you want it changed (pitch, cup, ect). The reason you get more RPM is because of the thinning and proper balance. It also weakens the prop if you hit something.

E-mail me or post the details of your boat and your goals and the knowledge base here will help you get there and give you an idea of what it will cost.

use the original pitch, however you can expect to get a few more r.p.m.'s and that equals more speed from the same prop!