Well it could be a EFI issue but since it's a conversion and running well, only a hot start problem... try turning key on and let the pump run it's 2 seconds. Turn off for 10-25 seconds, turn key on let pump run 2 seconds. Rinse repeat 3 times. Then try to start. If it starts then inspect your fuel lines and see that the feed line is not getting to hot, like near exhaust.
What this will do is flush hot fuel from lines.