You can leave it in the tank but put a cap on the vent if it's going to set for awhile so it don't evaporate.I run the q-16 and thats all I do other than jetting carb up 4 jet sizes.

3120lb, small block, 10.5" tire, NA, through exhaust, full int, WITH 83/4 REAR, 9.0 at 150mph