Hi, I have an '88 wellcraft Nova 23XL. I never bothered actually checking the speed until last week. ( had it a year). It seems slow. WOT is 4600 RPM and 50mph. My little Glastron did 55. My mechanic told me WOT should hit near 6000 RPM therefore my prop is incorrect. I use a 23° stainless 3 blade prop ( can't remember the brand). The mechanic said try a 4 blade 24° prop. Is this the answer??

uhmmm which 454 ?? if its the standard 4600 is about max but you should be closer to 60. Even if you had a mag, you not going to spin it 6 grand..... maybe 5200...

is the speed gps??

It's an ordinary 330hp carb

Then your rpm and prop choice look right in the ballpark,,, your speed does look a little low...prop condition? bottom paint? triming it out???

Bottom paint needs done. I might swap out for a 502 if the 454 only gives me 50.

Then your mechanic is an idiot to say it should run 6000rpms. Not to mention he suggested a prop that will decrease your rpms.
You are right where you should be rpm wise and older boats have a deep x dimension and best with 3 blades.

I should have explained better, but thanks for all the replies. The mechanic wanted to know max rpm at wot. Only for 10 seconds. His theory was if its floored and it doesn't get up near 6000 I might have room for improvement with regards to prop choice.

Bottom paint will slow you down. Is speed on GPS or mechanical speedo? I would check tach and speedo for accuracy. Then what about trim as Phragle stated? Are you getting the bow out of the water at speed? Also your current 3 blade might be repitched or cut down in diameter or out of spec. Verify the basics first.

My mechanic told me:

WOT should hit near 6000 RPM therefore my prop is incorrect.
WRONG-Look at the manual 4200-4800 rpm max

I use a 23° stainless 3 blade prop ( can't remember the brand). The mechanic said try a 4 blade 24° prop.
WRONG-His prop suggestion should yield you about 4200 rpm

Is this the answer??
NO You need to talk to a marine mechanic or fellow boaters with experience.

As far as speed, I am not familiar with the Nova's performance but 50ish for that vintage seems to be in the ballpark for your engine.
Good luck.

You mechanic is still an idiot. I strongly suggest dropping your mechanic faster than a drunken fat chick with herpes.....