After all the wiring alone and the cost of a bone stock complete 03/04 motor i would just stick with a pushrod motor and go just as fast with some money in your pocket.
If you want to stuff motors into things it doesnt belong I suggest an LSx and xxxx chassis
Thats Juniors old car, pretty pricey for a car with 4:10s and a 6 speed with some body mods *EDIT* Dont put a blower on it unless you have or plan on building the bottom end soon. Also the heads only have three threads holding the spark plugs in....
Some new parts and a used block without rods and used pistons just wont work especially since its going to crack down the road. You would be better off selling the used stuff individually and trying to return the new stuff. The valley girdle and main girdles do nothing but hold it together when it cracks.