When i was doing my v8/aod swap last summer I tried to retain as much from the old truck wiring and parts. Used original oil pressure sender and coolant sender (for the 2.9/manual). I used original wiring for efi fuel pump and inertia switch, just a bit of splicing for aod and fuel relay ground wire. I didn't check to see if the inertia switch is working properly yet based on my rewiring the aod backup/neutral safety switch. But the backup lights work correctly. I haven't bypassed the clutch three position switch yet either, just zip tied it up for now to get the engine to start. I used original fuel pump in tank and had to use a Mallory Ignition 4309 - Mallory Fuel Pressure Regulators with the existing fuel lines and special 3/8 npt to nylon fuel line connectors (found on ebay for gm lines) which I think summit has. I used one wire proform hei distributor, but have not got a new tach hooked up in the cab. I tapped into the original ignition wire to power the distributor coil too. Been alot of work, but fun too. Just notes as to what I did, hopefully somewhat helpful.
As for the alt. mine had 2 harness plugs originally so I just use a 90 f150 alt that fit my 5.0 mounting bracket and just plugged in to my original 2 plug harness (internal regulator).
Starter used the original set-up as well 2 wire hookup + battery and small signal wire. I used a truck 5.0 starter for the aod/v8. Expensive gear reduced starter, that sucked.
I would suggest getting a service manual for your truck and looking at the wiring schematics and carefully tring to figure out each piece of the wiring puzzle. ONE thing at a time. Kinda how I did it along with reading the tech articles. Harwood proformance sells a manual that is also very helpful for the things you are looking for. $25 though
