Ryan Weaver's 1969 Olds Cutlass S W31 Club Coupe

[earntaz]

Ryan -- the heat riser when partially closed will force exhaust gases through the intake manifold (usually under the carb) to provide heat for cold/damp conditions. That will prevent icing of the throttle blades, etc. Down here in south Texas there is probably no need for that mechanism. But in the northern tier states including Canada I would run the heat riser. That will cutdown on how long you may need to warm up the engine before driving. TAZ