I am running a 1991/1992 volvo 454 with 330 hp and a duo prop drive. Does anyone know what the max rpm this engine should be running at wot? Engine runs great, timing is good, new fuel filter and only runs at about 3800-4000 rpm. It has been like this since I bought the boat three years ago, Is this right or is something wrong? If I change my props will I raise my top end and slow my cruising speed? Thanx in advance for any info guys!

I had a 1991 454 it was a Mercury and a bravo one but that should not make a difference in the RPM's of a big block. Mine top RPM was around 5100. Sounds like you may have to much prop.

5100 is a touch high for a stock 330. You should prop the boat to put you around 47-4800 at WOT.

Thanx guys...but will changing the prop create a higher rpm to just cruise at a lower speed?