I need a bigger prop but how big
 

This is for my old boat... Its a 20.5 ' Nordic Crestliner with a 330hp 7.4L Its spinning a 23 mirage 3 blade at 5300 rpm. I feel this is two high for this motor and would like to se it around 4800-4900. I used a 4 blade on the boat once and it didn't like it. I would like to stay with a 3 blade. any suggestions

you might try a mirage plus, if you only have a mirage, same pitch should lower your RPM by 150 to 200, good luck

I would think a 25" Mirage plus would drop the rpms by about 500-600. 5300 rpms for a 330 seems way too high.

I would first double check the tach reading it sounds a little high and the engine should be on the limiter before 5300. If the tach is ok then the 25 mirage will reduce it by about 400 a 23 mirage plus should reduce it by about 200.

I believe the tach is okay. That puppy is screaming. I never held it at WTO for more that a 15 - 20 sec. I did some work to the engine and when I was done I got 400 more rpms out of it but I never changed the prop. The new owned is a friend of mine and I don't want to see him over revving it and blowing the engine. That's all I need. For some strange reason I have a feeling I will still be doing all the work on the boat if you know what I mean :rolleyes:

So should I look for a 25 mirage or mirage plus??? even if the R's are between 4700-4900 I will be happy but 4700 would be the safest bet.

A mirage plus is harder to spin I say 25 mirage you'll drop 200-300, Mirage plus 300-400, A local prop shop has a used 25 mirage I tested I think he wants $300 call and ask him B&B Propeller in Richland Hills TX talk to Bobby and tell him Jason with the Baja sent ya

I would think Performance Marine would have a used 25 mirage around to try. If you know Doug Smith I think that is what he is running as well. Maybe he would let you try his.