The diff is a standard Hotchkiss type open differential. Changing to a different bolt pattern will require redrilling the axle flanges. a good machine shop should be able to do it, but for the cost, you could probably find a differential that's already got the correct bolt pattern and perhaps a higher gear ratio. Pretty much all Chevy RWD cars and S10s ran that bolt pattern '49-'04. There are some exeptions, the '91-'96 RWD Impala uses the 5x5 truck pattern.
