slade I think I remember seenig some that do have vac advance on them.
but mostly to get into a decent timing setup you need a TPS sensor and MAP so you know load on the engine......by the time you add that might as well toss in a temp sensor and a couple injectors and call it EFI.
if I were you I would keep my eyes peeled for an older stand alone EFI that is batch fire or relys on some factory ignition parts (not a DIS system) and look into getting a used setup for cheap. my friend bought a used older haltech that was fuel only/batch fire for $200 just because it was a good deal. I am looking to pick up an old EFI box off my schools fsae team. the box I migh tbe getting was designed by on of our students in 2000 when her wanted a cheap EFI setup for his twin turbo pantera. he designed and sold these kits for $300 at the time. it tunes like a carb (set idle mix, accel, power, WOT and I forgot the last one....all just dashpots on the side of the box.......designed around GM components so cheap to toss together)