1988 Buick Regal Buick Regal Limited 2.8 V6 won't spark

Electrical problem
1988 Buick Regal 6 cyl Two Wheel Drive Automatic

Hello there,

I've got a 2.8 V6 Buick Regal Limited from 1988.
Two weeks ago I replaced both headgaskets since one of them was leaking water into the engine.(The engine ran "normally" before this operation)

But after installing the engine won't start anymore. The engine cranks, and the cilinders appear to get fuel, but there is no spark coming from the spark-plugs. All other electric systems of the car (dashboard, radio etc) work just fine.

I've read multiple possible causes like faulty oilpressure-sensors, cam-sensors and crank-sensors. But I would like to get some more information on this before replacing any parts since I live in the Netherlands and parts aren't very easy to obtain down here.

There is one remark I have to make about the car, that is that the lightswitch-unit has been removed and sold during the "headgasket replacement process". Ive sold this unit because the car will be used in an amateur car-rally assuming this switch wouldn't affect the running of the car.
Could the abcence of this switch maybe be the cause of the faulty ignition?

I hope te hear from you guys!