Reply to "shear pin on Distributor"

Once the powertrain is out, besides the list you mentioned, you can also do the following:
1)- remove the gas tank and clean all the debris behind it, rust-proof the area, then paint the tank. Stock tanks were unpainted as the car came from the factory and some have actually rusted through from the outside. If necessary, you can dump out debris and clean the inside of the tank. The tank cannot be removed with the engine in place.
2)- Rotate the rubber separator washers in both motor mounts. These tend to collapse at the inboard sides from the weight & header heat, putting a bending moment into the engine bolts, which them break. If you have broken bolts, they're a h..uvalot easier to remove from the block when its out of the car. Do NOT replace the rubber separators with aftermarket urethane. It melts from header heat and really makes a mess!
3)- Replace all the steel freeze plugs in the engine. Any stock mild steel plugs are at least 32 years old and are ready to perforate. Only one (1) freeze plug can be accessed with the engine in the car.
4)- this is an ideal time to change the stock timing chain to a double-roller chain. Clevelands are VERY hard on cam chains, often wearing a stock silent chain out in 15,000 miles due to the heavy valves & high rpms.
5)- if you can afford it now, every 351-C needs a 10-qt, fully baffled oil pan. A stock Pantera corners so hard on modern tires, the oil rides up the inside of the block, starving the pump & bearings. Look at it as $500 worth of insurance.