[Chrysler300] Richard with the missing 300G. if it is popping back out the carb.in 50 years running a garage here is what ifound. worn cam shaft lobes.they were mostly small block chevys. the hardest one to figure out was a chrysler 300 . it popped back out the carb .compression 130 psi.it was a weak valve spring on the intake valve. also broken valve spring crack in distributor cap. firing 2 cylinders at once when accelerating.check that out . larry