"the timing light shows #1 firing about an inch before the top lower belt, or approx. 135 degrees retarded."
Don't bother with the timing light until you get it firing.

Remove the distributor cap and rotate the engine to TDC. Ensure that the rotor is lined up with the line on the distributor rim by loosening and rotating the distributor. (Thus #1 cylinder will fire at TDC. You can adjust timing after you get the engine running at TDC.) Tighten down the distributor.

Replace the dist cap and check that the firing order is 1-3-4-2 clockwise.

Try starting the engine. If it doesn't start, check for spark at each plug. I carry a spare spark plug which I use to check for individual spark without having to pull spark plugs (just spark cables).
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1980 245 Canadian B21A with SU carb, M46 trans, 3:31 dif, in Brampton, Ont.