1987 dodge will not start when hot

Gentlemen, Ladies,
I have a 1987 Dodge ram 150 with 318 v8. The truck will starts fine when it is cold but when it is hot it will not start. I changed the starter three times with no result. I even change the starter relay with no result. I am just about ready to burn the ----- truck.
any suggestion will be helpful.
Oh yes!!!.all I also just replaced the engine. "Yes", the eng. will turn over bug there is no fire.

You gotta be kidding, three starters, and one motor...

When you say it won't start, will it turn over when hot, or not? If it won't turn over, then you should probably check all the voltage regulators, relay and such, if one of them is off it could quit working when warm. We had a similar problem on an older Dodge.