I have an 81 Riv draw through engine I used in my sand rail before changing to an 87 GN engine. I used a 79 dist. Engine ran very good on 110 race gas, but I would like it to run on pump gas. How much boost can you run with a BTM and pump gas? Engine is fresh,has 1175 miles on it. Has anyone tried using vac. advance on manifold vacuum instead of port on carb? A friend did that on a Pinto powered sand rail. His claim is boost "blows" advance back to below what it would be if disconnected.Skidman.