oh it most definately IS an interference engine.
IF you crank the shaft by hand and put the timing mark at tdc, you could pull your number 1 plug and drop in a screwdriver then watch it's movement as you crank by hand. I'm sure there could me many other causes so I wouldn't go tearing the front of the engine apart yet.
if your distributer died, you could still get spark but just not at the right time. When you are at TDC (or 5 degrees before), you cn also pull the dist cap and look at where the electrodes are. should be ready to fire on no 1