SBC prop question

Hey guys I know you say on the 2100 w/ 300 offshore you have been using the turbo lighting and then having some cupping done and running 5900rpms. My dad just got his boat last week and with that prop and no cupping it runs 5500rpms. My boat by mistake came with a turbo 1 but ran 5800-5900 and a little faster then the lighting.

Now we thought about getting my dads cupped but being that its already at 5500 he doesnt want to lose anymore rpms. Wondering why the rpms would be so low. What kind of differences did you see in rpms before and after cupping. Thanks

Depending on each boat it can vary from just a 100 up to 5 or 600. Our prop guy is currently working on a few right now and trying to gain some rpms with them while still increasing performance.

Thanks. Knowing that you guys are needing to gain rpms makes my situation better. Thats what we are going to do with my prop next week.

another question I guess would be what mounting hole are you using?

The factory setting and the one we have been sticking with is the second hole up.