I picked up an 89 chevy K2500, smokes for a few seconds after it sits a while. I've replaced the valve stem seals on my dodges but chevys rocker arms have to be adjusted on hydralic lifters. How do you know when is set right. last time i did it i wiped a cam in no time flat. the motor has a ton of miles on it and I'm not quite ready to do that. Working on the exhaust and tire first.