Try to get an induction (adjustable) timing light. They really help in setting the advance.
Your backfire leaving your ears ringing is alarming! Is it though the exhaust or through the carburetor?
I think you are correct to start looking at your timing. Also, check that your distributor is not loose, or worn (grab the rotor with the cap off and see if there is wobble).
Lean condition can also cause backfire, say a clogged fuel filter or weak fuel pump.
You can use an ohm meter (multimeter) to check your spark plug wires for problems.
I doubt your plugs need replacing but you can check them (post a picture) to see if you are running lean or rich.
You also might check and see if your distributor advance diaphragm is functioning (just suck on the hose while checking the timing to see if it functions at all).
Clean your plugs with a wire brush.
You can set the points gap and timing separately. No order critical. Inspect your points for evidence of burning.
I would look for carbon around the manifold gasket to find an exhaust leak. (It is hard to see the rear and underside).
Your backfire leaving your ears ringing is alarming! Is it though the exhaust or through the carburetor?
I think you are correct to start looking at your timing. Also, check that your distributor is not loose, or worn (grab the rotor with the cap off and see if there is wobble).
Lean condition can also cause backfire, say a clogged fuel filter or weak fuel pump.
You can use an ohm meter (multimeter) to check your spark plug wires for problems.
I doubt your plugs need replacing but you can check them (post a picture) to see if you are running lean or rich.
You also might check and see if your distributor advance diaphragm is functioning (just suck on the hose while checking the timing to see if it functions at all).
Clean your plugs with a wire brush.
You can set the points gap and timing separately. No order critical. Inspect your points for evidence of burning.
I would look for carbon around the manifold gasket to find an exhaust leak. (It is hard to see the rear and underside).