trying to figure out correct props scarab 300
 

I've got a 78 scarab 300/ scarab II 30ft model with 2 502's that were converted to carb from fuel injection.
Right now, i've got 4 blade 26pitch props that measure 15.5" across which came on the boat. It will top out at 65 at only 45-4600 rpm WOT. From what I've gathered, the 502's should spin 52-5500 wide open. I'm hoping it's over propped from the previous owner for a better cruising speed vs top speed, but I'd like to be able to get every MPH I can get out of this boat. I really thought I would be able to see 70 out of it.. What size props are people with similar hulls running and what speeds are you seeing?

Try these props first: 23 Mirage three blades then try a pair of 23 cleavers if you can find a pair-----------The cleavers will give you the best top end speed but your revs might be too high to run them .......This is assuming that you are still running the TRS drives 1:50 ratio... If the revs are too high you might have to go up on the size a little. The cleavers are surfacing props and need to be trimmed properly and they might give you a little problem coming out of the hole,need a little tab. Good luck !!!!!

Jim

Four blade in that setup will likely eat some MPH. Drives are deep and the boat is heavy. I think Cigboat1 hit the nail on the head. Mirage Plus props are good all around props. If you get a set that's "ventilated" (has little hole at base of hub) works better if the plugs are in the holes (my experience) If you can find a prop shop in your area that will work with you on trading props, you can dial that puppy in. If there's not one close, check with a marina. If not there, I think one of the marine folks that advertise in the "propeller" section offer trades, but there's shipping back and forth. Getting you hands on the most props available is the best way to figure it all out!