hello i need some help with some things regarding the engine in my truck i am currently trying to decide whether a detroit diesel engine or a 12 valve cummins would be better suited for my 1978 gmc k2500 and which one would be cheaper and more cost effective i have been told a cummins is better but also a detroit is better so i need some help from people that know cause i dont know crap about diesels but am trying to learn any suggestions?