I'll investigate the difference on my next valve adjustment. From the insights I've read here it sounds like I might be experiencing the first signs of valve wear. The engine does have 187K miles, smokes significantly when cold but very little when warm, is not eating any oil that I can tell, has no cold start problems (it's not very cold in CA where I live) and seems to have reasonable power for a non turbo. I will do a compression check soon. What type of readings would indicate valves not seating correctly or worn guides?

Thanks for the info,
Rusty