Timing, 6.6 mm LIFT!

['956Wheel]

First let me post the specs and modifications:

1995, 3500 5 speed, TST # 8 (stock position) AFC housing 1/16" from all the way forward, boost elbow (with the plate).

I put the plate in to help towing up grades, noticed heavy knocking up grades with load. Suspected timing.

Upon checking the chart in the D.C. manual I see 12.5 BTDC (stock for my CPL) is obtained by setting pump lift to 4.2mm.
Checking the timing I find that the pump lift is 6.6mm. I set it to 4.4mm (13.5 BTDC). Idles nice but when RPMs are raised (no load) BIG smoke screen....I mean BIG. WITH NO LOAD.

I turn the star wheel AWAY from engine 30 clicks and get approx a 40% reduction in smoke. Turn the wheel to 50 total clicks (same direction) some smoke but a lot less, these adjustments are all done with just "driveway conditions". A test drive shows a lot of smoke, at take off and loaded up acceleration, some at reving with no load, pre turb EGT seems to max out at 1100.

Before getting into checking and changing the timing the truck would run like a cheetah with its butt on fire, with a limited range (RPM) of power....1300 to 2000 approx. Now it runs with power that is "softer" what I mean by that is the former would rev like it had no flywheel.

Now the question (s) :

On timing 4.2mm lift =12.5 BTDC and every 1/10mm more increases the timing by 1/2 a degree so what would 6.6mm equate to in BTDC. If I figure right that would be 12 degrees advanced beyond stock! 24.5 degrees BTDC

IS THIS POSSIBLE?

Would it run as described as above

Should I keep tightening the star wheel (away from engine)?

Why would it smoke just gunning it in the driveway??

The mileage (combo, city hwy, empty) was 19, what should I expect now?

Mike