Loss of power and speedPossibly prop related

" First...Thanks to those who

" First...Thanks to those who have helped me in the past!
I hope this one is easy.
Last year, my 1976 Bayliner ran 32 mph @ wot.(4800 rpm) It has a Volvo 170. It would plane in about 8 seconds. The last time I took it out, I destroyed the prop. Over the winter I ordered a new prop using the exact number stamped on the old one (Michigan 082021 15x19) . The first time I took it out this year, the best I could do was 25 mph and would max @ 4400 rpm and I was forced to use the trim tabs in order for it to plane. According to the manual the max should be around 4800 to 5000 @ wot. I replaced the new prop with an old spare to see if the prop was the problem. I was able to plane rather quickly, but the rpm was exceeding specs.( I stopped at 5000 rpm (but only 20mph)with more to give. Here's the question...Is it possible to repitch a prop? I'm thinking the prop I destroyed last year was not the same pitch as the new one, even though I ordered the same model number.
Thanks for your help! "

" Dan,
I have had the pitch c

" Dan,
I have had the pitch changed on a stainless steel prop but I don't now if it could be done on an aluminum prop.
Witch prop do you have?
It sounds like the new prop has more pitch then the old one.
Check with the local prop guy maybe it would be better to make a swop with a different pitch propeller and see what kind of difference it makes.
Stan "

" Dan, The LOWER THE PITCH,

" Dan, The LOWER THE PITCH, the lower speed, the higher the RPM and jump out of the hole to plane. Conversely, HIGHER PITCH, lower RPM, more speed, poor jump out of the hole. Have your prop checked for pitch at a prop shop then adjust accordingly. Change of one pitch makes a change of about 200 RPM, as a rule of thumb. Have a great day. "