LOOKING FOR PROP

[CDEVIL2]

I HAVE A 2003 21 COBRA 350 MAG THRU HALL EXHAUST.IT CAME WITH A 3 BLADE S.S. 48-13702 WITH 21-P.WHAT SHOULD I RUN TO GET MORE SPEED.

[mtndewdrops]

CDEVIL2:
I HAVE A 2003 21 COBRA 350 MAG THRU HALL EXHAUST.IT CAME WITH A 3 BLADE S.S. 48-13702 WITH 21-P.WHAT SHOULD I RUN TO GET MORE SPEED. What drive are you running? Bravo 1?
1)Find out what RPM at WOT (Wide Open Throttle) your engine mfgr recommends.
2) What RPM at WOT are you running?
A Larger number in Pitch = more Top End but sacrifices your hole shot and low end power. You want to work within the limits of your recommended RPM...
I have an Essex Sterling 21' with a 350 MAg Bravo III and run a 3 Blade 26 Pitch and run mid 60's.

[steve@kps]

That looks like a Mirage part number.
I'd think you would have an Alpha One lower unit. That mirage may be too much for it. The diameter is too large for the Alpha. You may want to either thin the blades, to reduce weight. Or look for a vengeance. in a 21p or 23p. The revolution 4, would make a good 4 blade prop, for the alpha one.
If you do have a Bravo One, lower unit, then it's a whole new game.

[TCHB]

I do not think you call pull a larger pitch prop with the stock small block. My old boat would WOT at close to 4800 with 21P prop that you have. I had it cupped and it was to much and had to rework the blades.