Dad got the 63000FLT's installed and we are less than impressed. All spark plugs are harder to get to than the 31104FLT's that I have and the #6 spark plug is totally buried, will have to unbolt the dipstick tube(PITA) to get it out each time, not to mention the fact that he had to grind on the frame and A arms in about 4 different spots and the Z bar still rubs when you push on the clutch pedal. Needless to say, after two days of fiddling, he's pulling them off and putting the Hedman's back on.
Hedman's are probably fine, but his AFR headed 383 is pushing 500HP and 1 1/2" headers are going to kill some power. The 31104FLT Flowtechs I def don't look like they'd jive with the z bar either. Anybody know of any larger headers (1 5/8 or 1 3/4") that'll work with factory 4 speed set up?