if you have no 12v at coil + when key is on then you have break in wire from keyswitch to coil.

I would still check the engine oil pressure switch and see how many wires going to it, if more than 2 then check the switch and wiring, sometimes they have ignition tied into oil pressure switch to kill engine if oil pressure drops, if switch is bad then engine will not start.

Also open the panel on the front of the steering column and check the fuses in the fuse block there, they are bad to corrode up and have bad connections.