Accurate horsepower calculator/ desktop dyno?
 

I need to know which is the most accurate horsepower calculator/ desktop dyno program. I cant dyno my engines but need to get a reliable guess what horsepower they are making, so I can have better info for choosing props. I have some baseline info on what Merc rated my engines at originally and how they differ from original. To my knowledge adding an intercooler (turbo system) does nothing for horsepower, it just makes it possible to make more boost and/or more resistant to spark knock.

Intercooler on your set up should be worth a bunch in power vs a non intercooled motor. How much boost you going to run? How big are the cams and what heads you going to run?

The engines are Mercury 475 Turbos (gale banks draw thru systems) My boost is currently set at 10 lbs but I want to set it back at 15 lbs. I'm pretty sure that the original boost was 5 lbs from the factory ( TurboJack would know for sure) engine is a 462 BBC 7.5 compression... Cam is a Comp Cam hydraulic flat tappet turbo grind. 226/ 218 @ .050 max rpm of 5400. single 800 cfm holley. Stock GM cast iron square port heads (no porting).

Gale Banks rated the 454 Stage III kit with 15 lbs of boost at 850HP, You could increase the size of the bypass in the turbo housing to reduce the boost to 10 lbs & I think Gale Banks rated that at either 725-750 hp. Banks had there own cam. I remember trying it and I want to say we went with the LS7 cam back then since we liked it better. . My memory is fading so not exact sure on the Chev cam we used.

http://www.performanceboats.com/atta...1&d=1380494668

Just posting this picture that I found on the web showing the stage 3 setup. This one uses a dual intercooler. The less boost / HP ones used a single intercooler.

I use the same intercooler (actually a PFM brand), but my exhaust manifolds are the OLD iron rear exit log manifolds.

I also have adjustable wastegates on mine, which are currently set at 10 psi