Gaps

[Markus]

What are the pros/cons of setting plug and valve gaps to minimum, nominal, and maximum?

 

[shojuan]

Minimum means it will take the longest for the gap to grow out of spec.
Maximum means the fattest spark assuming the ignition system is up to delivery enough voltage (and the stock SHO system is).
Nominal is a happy medium.

I think I set mine pretty close to the minimum when I gapped the new plugs in September.

 

[sdpatt]

For the valve gaps, the minimum setting also gives a longer span of time and wear before the gap grows out of limit on the high side.The minimum gap also provides minutely greater valve opening and less impact when the cam lobe strikes the shim. Maximum gap results in lower valve lift and greater impact of the cam lobe on the shim and little margin for wear.

The minimum gap is specified to ensure the gap remains positive during all operating conditions and temperatures. The maximum gap is specified to prevent accelerated cam lobe and shim wear from the greater impact energy and to ensure a minimum of valve opening.