1978 Monte Carlo vacuum line diagram

This car was shifting gear slow and just needing to apply the accelerater all the time.( like it wouldnt shift into final gear maybe) any ways my mechanic was told the Thermostatic vaccume switch needed replaced. after replacing it and hooking up some hoses that he said were not hooked up right , the car runs like **** thats if it starts First it overheated right away (which it never di before)then with some adjustments to the carberater this got better but my heater will only blow cold air and we have single digit temps.Tryed to start it this morn. and it like backfired but under the hood turned it over a second time did the same thing and smoke came out from under the hood on the drivers side . Wont start at all. Help I need my car!!!