[Rossba]

The Cleveland and windsor are all the same rear end.
The 5.0 ran different balanced fly wheel with the bob weights being 50z on the opposite side.
The pre 1970 windsor's ran a smaller flywheel 157tooth with 164 tooth after.
They are the same size as the cleveland but balanced different.
The clutches are mostly compatible but the flywheel may need to be drilled for pressure plate pattern.
The bell housings are different from the 157 tooth to the 164 tooth only in the starter motor bolt pattern is half a hole out.

The 5.0 is different in many ways.
If you are willing to run all the 5.0 accessories then it is a simpler because there is no balancer that suits the 5.0 to run a v belt.
From AU on the exhaust headers had a different spark plug angle so the earlier headers wont fit.

The cheapest option would be repair the cleveland and put a carbie type injection unit on top and decent exhaust. You can also improve torque for the task intended over the 5.0.

The 5.0 could be easy if you get a wreck but we found in a f100 they are slightly under powered.

The best option as stated earlier would be to get a conversion kit and put a LS into it. They make good power and economy for a standard engine.

At the end of the day it depends on what you want or need out of it.
If you dont drive it ofter the money save by KISS can buy a lot of petrol but if you do many KMS then the fuel saving can pay the conversion off quicker.

Ross