What should my top speed be?

[Blue]

I finally got the new boat in the water. Sold the 19' aquasport and now I have a 1973 20' CC with a 1993 Johnson 150. The difference is incredible! Like night and day!

The last boat had a slightly older 150 but flew.

This seacraft has a 14.5 x 19 stainless prop. On the GPS I am getting 32-33 with a 1/4 full tank and one person. My tach has issues and as far as I can tell can't be trusted. It shows idol at 1500 and WOT off the gauge, like 7000 +.

This seems slow to me. Who out there has a similar set up or who can give me insights on where I should be.

Thoughts on what to change?

I looked through past threads and am finding that prop as a good choice so I turn it over to those who know the boat.

Thanks for the help