Powerglide is 1:1 ratio
           5000 rpm= 5000 rpm
           More weight in boat = slower boat

My mistake A Powerglide was a poor example

Ok My question is If I designed my motor to fit further forward and my pump further back on a 21' daycruiser and put a 2 speed powerglide between the two wouldnt I be able to get a TREMENDOUS amount more top end out of a relative standard big block?

Nope. You need to remember that transmissions don't multiply power. They do multiply force, in this case torque, at the expense of rpm(think LOW GEAR). They can also multiply rpm at the expense of torque(think OVERDRIVE). In each case , HP available at the output shaft is the same as the engine's HP at the crank MINUS the HP lost in the transmission.

I looked into going with a Lenco single speed so that I would have a neutral for use out of water, but a Jet-a-way is cheaper. Still can't afford a Jetaway 

FWIW, the pump curve for most Berkeley type pump impellers puts the optimum RPM at bout 5200 RPM, easily obtainable with any V8 internal combustion engine...(well almost any)

Now when you are running a turbine that spins 26,000 RPM, then I would expect to see some sort of gear reduction...

The Z drive deal has been around for a while, I will still have to wait and see if the benefits out way the drawbacks....KISS....

Perhaps the biggest performance gains that can be realized is with impeller design, you don't see much because the engineering is stupid expensive, as is the R and D phase...Just to sell a few hundred impellers a year would be an exercise in frustration because your design would be copied before you recouped your engineering costs....nature of the beast...

And yes....Been there and done that.

GT