Don't get discouraged. 1 step at a time.
You know how it came a part. Lots of people do engine upgrades in early cars. Try to get the early car back together, with the engine upgrade. Lots of info here, ask specific questions each step of the way.
Wiring diagrams are here:
http://www.pelicanparts.com/911/911_Parts/911_electrical_diagrams.htm