Outside the frame is an option for Ibeam / Gearbox trucks, the Ibeam trucks have many header options, they are much easier to fab up or modify something to work.Make your own headers that exit outside the frame. Much better. less clearance issues. Speedway Motors has a weld up kit for SBF for $150. on sale now for $115. Comes with plenty of pipe, Collectors and flanges. I used it on my 351W swap recently.