360 dies at idle, but not when in gear ??? Huh?

I'll recheck the vacuum numbers. Ignition is a mopar hei with an msd blaster coil. I rechecked the base timing and it was more retarded than 10 so I set it back to 10, it doesn't die putting it in gear. Shifts fine then when you put it in park it'll idle for 10 to 15 seconds and die. If you rev the engine it'll stay running so it's a fuel problem in guessing