First of all, old Scouts are just plain cool! They were IH's push into the off-road capable arena, a Jeep approach. In your first post you say, "Tank was cleaned and fuel lines replaced over the winter." That can be OK, but it's also hard to clean out an old tank completely if it's badly rusted, and it sure sounds like you've got a flow restriction somewhere. What process did you use for cleaning the tank? As I recall, Quadrajet's were even more susceptible to plugging than other carbs of the day, and good filtering is critical.