91 ford econoline 250 351 Cleveland
I have a 351 Cleveland will start and run but when
you shut it off after 5 minutes and then try to start
it again it won't run while it hot
A Cleveland? Are you sure cause that is not what it came with originally, a Windsor was the most popular with the 460 as the next engine.
You need to find out if it is spark or fuel that goes away, you will need to get it into failure, then spray some starter fluid in the intake and see if it will fire and run briefly, if it does then it is fuel, if it doesn't then it is spark.