My '70 is a LWB, 2WD, 390-4 spd manual 9.375 rear (3.50:1), and has the dual front shock setup.Is the 2x shock thing rare (of value), or just a way to defeat the whole "rides like a car" part of the advertising?

Mine is a "70 F100, 390, 4 Spd., 2WD, with the extra tank at left-front of the bed. Since it looks like a new exhaust is in order, anyone have thoughts or experience regarding dual exhaust (headers or stock manifolds) running around that extra tank? Searched this forum a bit, but nothing was...