Now correct me if im wrong but if the valve were to hang up in the guide, the valve would hang open every revolution thus causing a miss and a tick. But it does not miss just ticks. The exhaust valve guides have an oil hole to "lube" them by design and do not have a stem seal. Chrysler must have had a reason for this. If the cam were to blame, the engine would miss. I had a cam go bad on me in a chevy and I know that death sound. The only other thing that I can come up with is the lifter bore and or the oil supply.