That's the oil pump. The tabs are there to keep it from rotating in the housing. Bet you started to tighten down the housing when it wasn't seated right.
Holy cats.... Advance Auto actually lists the entire pump as available: http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_x_10185251-P_x_x?cm_mmc=ACQ-_-Google-_-enhancedRM-_-10185251&ci_src=17588969&ci_sku=10185251&ci_gpa=pla&ci_kw={keyword}&gclid=CNzj853Pr7QCFetDMgodckgAUQ#utm_source=acq&utm_medium=google&utm_campaign=enhancedrm&utm_content=10185251
P/N 18676.47. This looks like the Omix-Ada part number, a search for it returns a bunch of stuff.
4wheelparts and Quadratec also list it.