I do this alot myself
my 85 truck...has the ecu and elect dizzy
I get a points dizzy from auto zone
install a pertronix points conversion in the oints dizzy
drop it in the engine,leave all the wire harness and ecu in place
drop the neg wire on coil for elect dizzy
use the keyed hot wire from haness with red wire from conversion on + side of coil
add black wire from conversion to neg side of coil
done,been doin it that way for yrs and no probs
if you just use points...
drop in the dizzy,drop elect dizzy wire from neg side of coil and hook up black wire from points to neg side of coil...done
I did change points every 3-6 mounths though
cant really tell it swaped over unless you know what wires to look for
scratchin