Help!

[7TZ]

My 68 AMX starts fine when cold, but when warmed up and shut off, it wont start again until it sits for at least 5 minutes. I thought it was heat soak with the starter cause I had headers. I removed the headers and put on stock exhaust manifolds, but no difference. I sure dont want to stall out on the road and block traffic for 5 minutes. Anybody?

[7TZ]

Let me clarify. When warm the engine does turn over, but it acts like it doesn't have enough voltage. Slowly turns over, until 5 minutes and fires right up.