Quote Originally Posted by absintheisfun
I know very little about turbos, but the more I read, the more interested I become. I'm pondering the possibility of using a twin setup on my build, and want to ask the experts out there if this is a good starting point for a block: (Its a GM Crate 290horse/350.


Horsepower:290 @ 5100 RPMTorque:326 @ 3750 RPMCompression Ratio:8.5:1Block:Cast Iron 4-Bolt MainCrankshaft:Nodular IronHeads, Chamber Size:Cast Iron, 76ccValves (I/E):1.94"/1.50"Camshaft, Lift (I/E):.450"/.460"Camshaft Duration @ 0.050" I/E:222°/222°Intake Manifold:Not Included
I'm far from an expert, but I have run a couple of boosted engines. With the heads on that motor, I think this will be your limiting horsepower factor. With either superchargers or Turbos, tuning is critical...read...read...ask...read...ask. Meltdown is quick if not done correctly. I think if you keep it under 8 psi, you should be good. I have found that with factory timing on a 9:1, cast iron heads, it will ping at peak torque around 6 psi with 91 oct. So anything under 8 psi on a 8.5:1 cast iron head motor should be fine. I would start at 5 psi and work from there. Intercooling will allow you to increase roughly 2 degrees timing or 2psi boost with the same oct.
There are ignition boxes you can buy that will retard timing under boost to help aid with detonation.

With this, I would think you should get about 100hp. Don't know what the GM create engine is rated for, but I don't think I would go much more.