Originally Posted by low900rr
Since its from an s10 blazer im sure its not the HD. The HD's are probably from the 3500 IFS fullsize trucks. Whats different about em a wider chain inside???
WRONG! That picture I posted is from a 1992 S10. All the HD marked cases will have the 1.25" wide chain and gears. Sometime around 1995, they stopped putting the 1.25" wide chain in the S10 cases and went to a 1" wide chains. The 231C-HD has the same planetaries and chain width as the fullsize 241. In fact, that 6 pinion planetary set is the same one they use in the Klune V, Atlas 4 speed, and NWF black box. Its WAY overkill for the 231 case.
EDIT: On the pre-1995 S10 cases, most of them have the HD parts, even though they are not all marked with the HD stamp.