Were can I purchase these can they only be bought from the dealer or can I go to Kragens does it matter if i get one off a another model???
also I replaced my O2 sensor with a D16 o2sesnor cuz it was burnt is there a difference i was told o2 sensors are all the same but this is from a domestic head though that messes with old chevy's thats why im asking.

 

I'll sell you a MAP sensor for $15 shipped

What car/motor do you have? If it was originally 4-wire O2 then any 4-wire O2 will work.