I could'nt respond to ur answer to my question, retired parts guy, thnks for your help.i have the back engine casting numbers, k10, and 3970010...the ones I recently put were the front stamped numbers, someone also told me that because my dipstick is on the drivers side that it's a 305... I will keep on doing more research on it, if u have any more input??? I would take as much as I can get. Once again, thnks for your help.