2006 35’ Outlaw and I have 496HO’s and currently running 4 blade 26 pitch. Only getting 66 mph. What prop should I be running? Stock 496HO

What's your max rpm?

Getting about 4750 rpm at WOT. 66 mph.

Isn't the HO around 5000 WOT? Not familiar with the 35OL but maybe consult an expert like Brett @ BBlades, seems like you need to get your rpms up by having your props tweaked or dropping down in pitch. Maybe someone here with experience with the OL will chime in.

The HO is 4600-5000 rpm so your in the range and your slip is 15%. According to boat test, in made 72.5 mph at 5000 rpm. Don't know what props came with the boat but maybe 3 blade 26 or 4 blade 24 which would raise the rpm and reduce the slip

Hogheadsena,
496 Mag HO's have a rpm range of 4600-5000. The rev limiter is 5150 and we try to prop close to the limiter. 4800 will work but we desire 5000-5100.
If the props are Bravo 1's the pitch is actually 25.3. This makes your slip 13%. This is a normal for this hull. According to the test above, you would need to be able to turn 26.4" props at 5000 rpm to hit 72.5 with your 13% slip. That is obviously a ways off.

If it was my application, I'd try 26 BBLADES 4-SPEEDS and Lab the Bravo's or the 4-SPEED to get the best you can post testing.
Remember, every identical boat is different and most published tests are with new hulls, no gear, low fuel and often slightly exaggerated in the OEM's favor. Also, if the boat is new to you, more seat time and playing with trim and tabs could improve numbers.
Let us know if you would like to test some props.

Brett