Picture is to fuzzy to be useful other than indicating it is a Delco 40 MT starter. As a conversion it uses the same 11 tooth RH helical drive as other Cat conversions. It is not the same as an original factor D2 direct start unit.
http://www.ebay.com/itm/CONVERSION-STARTER-DRIVE-FOR-PONY-MOTOR-CATERPILLAR-ENGINES-11-T-/360930526875?hash=item540922c69b:m:mVUgy5ivbEUePhUBT-SFxWQ&vxp=mtr