Valve guides in stock Chrysler engines, /6 or small block up to Magnums or big blocks, should be .374 to .375 inches ID. Intake stems typically measure .3725 t0 .373 inches OD. Exhaust stems typically measure .3715 to .372 inches OD. Knurling works fine for stock lifts if done correctly, and will last hundreds of thousands of miles on a street motor.
