OK ,so my pickup(75K20)needs an engine . Lost number 5, no compression dead miss. NO TIME. Trying to keep grandson's 79 K10 going! 20 years ago son-in-law bought a 78 K20, drove it for 3-4 years and decided he was gonna "fix it up". It was a rust bucket all over so he took it apart' I mean TOOK it APART!! Cab ,fenders ,box, engine, transfer case, all in pieces. The only thing left complete was the turbo 400. Got aftermarket fenders, doors and tailgate. Sat for 8-9 years and finally decided to put it together. Didn't have a clue! He is/was a paramedic and had a friend 15 years older(my ex-brother-on-law) that would help him. My ex-bil was a really good guy and he's the only one in the ex-family I really liked. Anyway I knew he and I were gonna be the ones to get this thing together. On craigs list one day saw a 79 K10 for sale. Engine and trans in the bed. GOOD shape. Right!! Called, went and looked and it WAS in GOOD shape!! No rust anywhere. Bought it for $400 hauled it home and started on it. Talked son-in-law into a crate 350, he got the 400 rebuilt and good ole Ray(bil) built the t-case. Put everything together about 2 years ago and it runs awesome! Odds and ends to do. Finally about 2 months ago took the dash out cleaned up replaced all the bulbs and was putting it back together and spied an electrical connector and found out it went to the tach. All back together and waited for darkness and finally fired it and all the dash lights worked and the tach worked!!!! Wouldn't have guessed anything worked after all these years of sitting around. Anyway they drove it around and when cold weather hit, no defrost. I got it back last week and started looking, found there was no vacuum to the controls(a/c cab). Plugged it all back in and WOW Defrost works great, now. Eventually I will get it ALL sorted , so I can go back to mine