Anyone know if the Z22BR hull will handle more speed,right now i'm at 54 mph indicated and 48 gps speed.
I have the 350 MPI Mag has 300hp with an alpha Gen 2 with about 100 since a jasper reman. What type of speed will
i see by adding a 383 475hp stroker and a Bravo 1 ?

Tell us how you plan to get 475hp out of a 383?

Going by what the machine shop says 450 to 475. So is it not likely ? Omaha, lots of kin there.
My family is from a small town called Plainview...

Well, it certainly can be done, but things like compression ratio, rpm, cam etc required to make that power in a 383 often are not compatible with day to day marine use.

You add 150 hp you will add about 10 to 12 mph.

How much HP to be used day to day with no issues ?

Trying to get something reliable and get mid sixes. Is there a rule of thumb for speed ?

Yes, the rule of thumb is throw lots and lots of $$$$ at it and it will go faster, maybe...

Rule of thumb is over 1.0 hp per cubic inch is expensive and unreliable. Put a 454 in it. Aluminum heads and it is essentially the same weight as the small block you took out. But you spend 3 to 5k and speedo will say 62 instead of 54. It is a paid for reliable nice setup.

I just googled the boat..it looks to be less than a 24 degree bottom? and it has a pad? and your seeing 48 mph gps with 300hp thru an alpha?

Before you start building anything, figure out whats wrong first. If its the bottom I saw in the google pik, with 300 hp you should be 10 mph faster.