Yes 60G are the good ones
Yes, 60G's are the preffered plug in the AC Delco line. I think Bosch Duraterms or duratips are also ok.
I think Heath quit selling Wellman's due to short life expectancy. But they could have changed quality by now.
Here is something I posted a good while back. I think they start up as good as my OE ones and have been fine through the winter (not real cold here but a few starts in the high teens F).
http://www.thedieselpageforums.com/t...&highlight=60G
97 5spd K2500 Ext Cab short Bed ~160K miles.
TM, 3" downpipe & 4" exhaust, remote FSD, remote oilfilter, Gauges: EGT, Boost, Fuel Pressure, B&W Gooseneck Turnover ball, Prodigy Brake Controller. Hi-Temp Hydraulic Oil Cooler Lines.