I have two sets of plain full-length Comp series Hooker headers on two diff 64's with 350/auto, one has 700r4 other has TH350, both OE column shift. Fit great, no mods to truck, don't leak, don't hang down too far, exhaust is pretty well tucked(not enough for the low-rider baggers who lay frame tho). I did grind an 1/8" or so radius on the frame on driver's side just in case the engine torqued enough for header tube to hit the frame, but I really doubt it ever would. The tube clears, I just wanted a little extra JIC.
Hard to beat the sound of a 350 w/headers & dual exhaust.
