Just trying to see where I might be mph when I do motor swap over winter and I'm wanting to be somewhere in that range is the goal.

Not exactly what your looking for but I have a friend who is around 83 mph in a 33 avs with 600hp a side. So I assume you will need a good bit more power than that.

What motors does he have making 600? I thought 33avs ran 80 with 500s. I read a test on a 38svs with Volvo 600s 570 at prop doing 82. I have 2 zz572/620 crate motors I'm going to go thru they dyno from gm at 650 horse and torque.

i have an 2001 38avs with 800 naturals and xz drives the boat runs 93 mph on gps and is solid at that speed 32 4 blade props gets on plane with ease

Damn that's awesome. I think I'm gonna be somewhere around 650/700 after going thru motors. What power plants do u have making that kind of power? And Thanks for your info

Right at 80 with 500 HP Merc Bulldogs, extension boxes and labbed 30's in a 38 AVS.

Is that on GPS, Extension boxes help? I hear speeds of 75 to 80 with 500s. Motors I'm pulling out are 502 435/415 mpi 66/67 which is to Slow

Something is wrong with your friends picture. He either doesnt have the HP he thinks he does, or he has a bad set-up. A 33AVS will run 80-82 on stock HP500s. You can run 28s or labbed 30s on it with those motors.

The 38 AVS with the Volvo 600 DPX set-up will run 80+. A good part of that equation is the efficiency of the DPX drives getting the power to the water with minimal slip though so you have to keep that in mind when using that boat as a benchmark. Ext boxes will go a long way in helping you achieve optimum results along with adding power. Set-up is KING.

Yes, GPS. I have also heard Merc's Bulldog motors usually produced more than the advertised 500 HP, but have never dyno'd mine to confirm. I would echo everything Scarabman said... boxes and set-up!