Valve Adjustment for Performance

[Dougieb]

Hi All,

I am in the process of adjusting the valves on my 1972 Spider.
The books call for 0.017-0.019 inch for intake and 0.019-0.020 inch for exhaust valves.
Keeping in that range for the valves, where is the best place to set them?
I assume it is best to keep them at the lower end of that range, 0.017 for intake and 0.019 for exhaust.
But does it make that much of a difference?

Here are my numbers:
Intake: 0.020, 0.0185, 0.018, 0.018
exhaust: 0.015, 0.019, 0.019, 0.018
Three of the intakes are in the acceptable range, but if I am going through all of this trouble,
will it make a difference if I bring them ALL down to exactly 0.017?

Looking for some opinions/suggestions.
Thanks,

Dougieb

[vandor]

>But does it make that much of a difference?

No. As long as they are within the range you are fine. You may not be able to set them all the same, as the shims sizes are available every 2 thousands. So if you are at .018" then you can adjust it to .016 or .020, but not to .017 or .019.

[BEEK]

to answer your question exactly, valve adjustment does effect performance, and the tighter the adjustment the longer duration your engine will see from the camshafts. is this noticeable? only on a dyno! ideally you would want 0 clearance at operating temperature, this would be the best . but only hydraulic lifters can give you that. me personally,