there are 2 of the valves you mention one in the filter assy and one next to it in the block ( for the cooler ) plus a plug which has to be removed if you block off the cooler passages its a safety incase the stock cooler plugs out . and if he changes cams to a non snout style ( as he has the stock L-29 Fi cam in the block ) he was exploring his options incase it doesn't work with a carb . but I would say after seeing the durability of the single chain is to stay with it .