Most kits on the market are bolt-on . The Z32 requires a little fab work and there were not that many units built and sold ( compared to other Z models ) . My goal is to keep HVAC system because it has awesome HVAC compared to my other Zs , both of my 78 and 83 have no working HVAC after the LS1 conversion . The 83 is completely removed . Trying to get , at least , the heater to work on the 78 .