1976 Other Ford Models wont crank

I have a 1976 Ford Elite 400cubic inch engine bought it new 1976 had it in to ford, within a few weeks of new once the car heats up, it cranks over like the battery is dead or out of time. Ford said nothing wrong with it and never took it back after 30 years still does the same thing, any idea on what I can check first was going to replace battery cable wire and maybe remove distributor and make sure it is at top dead center when I put it back in. Have you ever heard of this with a ford before and should I just give up after all these years.