1986 5.0 won't start when hot

[mustang1077]

Hello,

I have a modified 1986 5.0 that won't start when it gets hot. It will barely crank and then won't crank at all when I try to start it hot. When the car is cold it will start just fine and after the car cools off it will start just fine. I don't have to jump it or anything. I have replaced the starter, starter soleniod, battery, and had the 140 amp alternator tested. The battery has been relocated to the trunk and has a good negative ground. I replaced the postitive battery cable with a 2 gauge wire. I have also checked the timing and set it at 14 degrees advanced. When the car cools and can be restarted the timing is still set at 14 degrees. This problem came about by itself. I did not make any mods when the problem started. I have not replaced the starter relay. Please let me know what you think.

[goodyear1984]

do you have long tube headers? how does the body to enging ground look?