Have you thought about picking up a drop out motor from one of the bigger wrecking yards on line? For about 1300 bucks or less you can get a complete low mile 5.3 iron block motor with the entire EFI system, computer and harness, front drive set up and all acces. Just a thought. Then do what you want with the heads and intake and cam.
I think one of the stock(close to 300hp) motors with an upgraded intake (that also fits under your hood) with a set of headers is going to be plenty of power to get your nova hauling ass in a hurry. If you look you can also get one with a transmission and it's controller for not much more. This would sure beat building from scratch and take a lot of the guess work out with the different computers, sensors, reluctor,.....you get what I am saying.
You could have the motor, trans, computers, fuel system, all mounted and running in the car for under 3k.
EDIT: Another reason for this is that you can have a 300hp motor all done cheap and never have to open the block. Mine is going on 175k in my truck with out ANY troubles. And 160 k of that was on the original spark plugs too. I am also running the original untouched transmission. Mine is a 2000 model 4x4 Silverado. So, why not? Bullet proof drivetrain for dirt cheap.