It seems that most failures I hear about involve the G80 Gov-lock carrier. When mine blew up, it was the spider gears/carrier that broke, and then the shrapnel took out the pinion gear. If you have the gov-lock, the first thing to do in strenghtening might be to replace the carrier.

 

I think that all 14 bolts would be 8 lug. But I agree that changing the carrier might make it stronger.

 

Not all 14 bolts are 8 lug, but the vast majority are. If you look long and hard enough, you will occasionally come across a 14 bolt SF with 6 lugs.

 

i have a 14 bolt and it is only 6 lug on my 95 K2500 so you may be able to find one

 

Considering the time and expense it would cost to strengthen a 10 bolt the 14 would be the better choice. There are 6 lug 14 bolts out there, hard to find but available.
You can also buy a 14 bolt axle and convert it to 6 lug. Look on the internet at some of the hard core off road sites, theres guys building all variations of axles out there and parts are readily available to build almost anything you want.