Keep searching for a 5.9 or a 360LA. might be a torque converter balance issue with the 5.9, others can chime in on that. Mod the trans crossmember so it has the same curved in scallop on both sides so the exhaust doesn't hang down low on that side. As said the 70 up alum water pump will be taller front to rear & not sure if that is an issue or not, others will chime in but if going for that get the later timing cover so the timing marks ain't partially obstructed like they are with the hose/marks both on the dr side.
