C15 valve lashings...AGAIN?!?!

Did my valve lashing on a Cat C15 a couple weeks ago. Set the intake to 0.015", exhaust to 0.03" and drove off into the sunset. However, something was wrong in toontown. At lower RPM (1200-1400), the motor clattered and knocked as well as idled rough and had what sounded like an exhaust leak "tick" at idle. Fuel mileage went from 6.5 to low 5.0 and pulling power was a joke for a 500+ hp tuned motor. So, I popped the valve covers back off and rechecked using the "go/no-go" style feeler guages. All were exactly where they were supposed to be. Ran a full gallon of Lucas injector cleaner through, as well as verified injector height; all +/- 0.005 to specs. Visually, everything looked good in the overhead and oil was getting everywhere its supposed to adequately.
Ran the truck another 500ish miles. The noise was pi$$ing me off, so I ran the valve check yet again and according to my Matco feeler gauges, were where they are supposed to be. I then tightened the valves down so that the valve bridge would still wiggle, but not lift up off the valve spring like they do when set to specs. Lo and behold! The rough idle is gone, ticking at idle is gone, fuel mileage back in mid to upper 6's and can pull the world sideways again! Anyone ever hear of this type of thing? If so, what was the verdict?

 

Yes, although I don't remember the spec I used. Jakes were never in question; always worked the way they should. Numerous posts on different forums all say 0.030" on exhaust and 0.0150" on intakes, so that's what I went with. In hind sight, 0.003" is about where they are now, although today I am going to be "adding a 0" to the specs I found and trying 0.003" and 0.0015" respectively.

 

Not an acert. Its a pre-emmission kitty cat.

 

Here is the order I did things originally:
1. Valve lashings
2. Jake slaves
3. Injector heights.
4. Double check all of the above.
5. Triple check valves.

And that's where I saw all the problems with 0.030" and 0.0150". Once I went tighter on the valves, all my problems and obscene noises went away and the thing runs like it should.