with the values of these cars with the corect engine I would go straight to pull the engine and then pull the heads and the pan. if all looks well its an easy put back together but there could be rust coating the inside of the engine that you do not want to break free and run through the oil. at minimum I would pull the valve covers and pan to see inside first the distributor trick I use is to point the rotor foreward before pulling and then replace in the same spot. doing that you can work on anything and not try to remember where TDC is. if there is a suspicion or unknown, then I pull the number one plug and put my finger in the hole while I turn the engine to TDC bob