How many miles on that old Chrysler 318?? If you are north of 130K miles, the plastic coated timing gear falls apart allowing the chain to slip and the timing to be grossly incorrect…
Remove the cap so you can see the rotor and rotate the engine with a breaker-bar on the crank pulley bolt…Rotate the crank back and forth as see if the rotor responds to this rotation. How far behind the crank is the rotor when you change directions…That will tell you how much slop is in the chain and gears…