Unfortunately, if your fourteen-bolt axle's got an 8-lug pattern, it means that it is a "full-floater" That extra hub sticking out, with bolts of it's own, allows the axle shafts to be removed without pulling the wheel, drums, brakes, bearings, etc. The Full-Floater 14-Bolt has a 10.5" ring gear.
The "Semi-Floater" version of the 14-bolt can be found under "heavy halft-ton" trucks of two generations ago. (Not duallies and not diesel) These rears have a 9.5" ring gear. They also already have the 6-lug pattern.
Give DriveTrain Direct a call, http://www.drivetraindirect.com and talk to Jason. These guys can build a 10'5" semi-floater. They call this setup bulletproof for good reason. Maybe they can convert yours to the appropriate hardware. They are in Corona, CA. (909) 272-0158, (800) 584-4327
Hang on to that thing until you find a place that can do the work - it's VALUEABLE!