Stupid question - what is the diffrence between the ZZ engine block and a basic 350 from a 79' K5 Blazer? I going to be buying one and need to know if there is anything special in the rebuild kit other then the 1-piece rear main. I don't know what year it is yet and just need to know if it is going to drop into my 79' without any problems? Thanks, Shane 79' K5 Body Hurting But Runs Great!!