i ran mine with my nelson tune all the time. i ran 31* n/a and then i had it pull 4* when on a 150 to 175 shot. i kept the afr at 12.9 n/a and when on the button i wanted it at 11.9 max.

 

Rule of thumb is pull out 1.5-2 degrees per 50HP

 

Every truck and combination will net you different max timing...
I run 29* of advance with a very effective exhaust system and 125-175 HP on a completely stock 5.3L. Fueling is key ... keep it reasonable to keep it together ... leaner is meaner but really is 5-10 HP worth nuking another piston?

 

Exactly, I know mine is running a bit on the rich side when I am sprayin and that is fine by me, less chance of the motor going