Cranks but no start, new coil,dist,module,relays wires. Have spark to plugs

1986 mercury 5.0 engine,have spark to plugs, have pip signal on coil
white/black wire,S/B on neg side, but only get spark when applied to positive
side?
Have new coil, dist. module,wires,plugs,map, idle cont. fuel pump, pressure
reg.30+pressure.
No timing sending unit,done by hand TDC with no 1 location on dist. cap.

This motor & od TRANS has been installed in a 1950 Ford with the the
original wiring WAS RUNNING for years this way until the fuel pump got plug
with varnish then all went nuts.now have a new tank lines ETC.
Need professional HELP.