Newbie intro and questions

[Jrbsx4 at aol.com]

Hello folks:
My name is Jim, I live in western new york,  I have an 83 AMC Eagle SX/4 
sport with the AMC 258 six and BBD carb.  I want to make my own "howell" like 
FI system.  I read some info on the net. 

I pulled the throttle body, ECM and a bunch of the engine bay wiring harness 
from a 87 Caprice with 4.3 liter.  Also got some, but not all of the sensors. 
 The ECM is a '746 unit, most of the references I see to the 4.3 show a '747 
ECM.  Whats the difference?

Also need to know where to find the wiring diagram for the ECM connectors (I 
guess these are call pin-outs).   Do the haynes or chiltons manuals show 
these..or do I need a factory manual.  I have a factory manual from an 86 
Sunbird, but the system seems quite a bit different.
Appreciate any help..
Thanks
Jim Bolton
jrbsx4 at aol.com