if you have a model # go to sears parts [link=http://www3.sears.com/]Here[/link] and enter it, some of their part #s will be standard and then search www.jsesc.com with some part#s or other sites to find a match, often they will list the true Mfg.

If you only have the engine there should be a Part# on it, or use this Model# 358.796131 it should be close to the same. Thats a much older unit and may be one of many Mfg's sears has contracted with. My guess as far as style is its Weedeater/???

I found a cross at M&D to POULAN part#530026675 ASSY-C'SHAFT & ROD
for the engine components, crank and rod assy shown.