Why do you think the chain broke? (chains don't break, it's usually the cam gear teeth).
To check chain for slack, remove the dist cap and turn the crank by hand, (Not by the key) when you see the rotor turn, stop, make a mark on the balancer with chalk and then turn the crank the opposite direction and stop! as soon as the rotor moves. check and see how far the crank moved. there will be some but not much.
If the chain slipped, it most likely at least needs some valves and or push rods.
I have a '87 5.0 Mustang GT convert. The drive trains and motors are the same in the Ranger, lincoln, T-bird, Astro van. (use the axles from the van or the ranger drivers side, they are the same, but 5 lug) The parts are every where.

Pat