[Triple Jim]

These engines tend to close the clearances with use, and it's worse when the engine is cold. When they get to where the valves don't quite close with the engine cold, it's hard to start and doesn't want to idle in a stable way.

I doubt if you'll notice much extra low end torque with only a thou or two more clearance, but I think it's wise to go on the big side of the spec since miles will make it smaller.