i have a 71 custom 10 with a built 350 in it, i don't know exactly what has been done to the engine for i just bought it, but i do know it has a big 4 barrel carter carb on it and i need better gas miliage and i heard that there is a plate you can buy to stop two of the valves from opening to pretty much make it a 2 barrel and i was wondering if this is true and where i could get one and if there is one if doing this to the carb is permanent or not and/or if there are any other ideas on how to get better gas miliage without just getting a 2 barrel or is that just my only option.