Your car's engine didn't get dirty overnight, so don't try to clean it "in a jiffy." Given the vintage of your car, there's probably some wear on the wiring harness, and likely some compromise in the waterproofing of things like the distributor cap and other sensors. You would be better served by using an engine degreaser, but using taped or rubber banded plastic bags to cover the electrics. Use no more water pressure than you would use by a garden hose on a rose bush to rinse, not blasting off stuff, otherwise you might find your car immobile until the water dries.