I was just on another site that stated that the Granada spindles would sit the tire and wheel back about an inch farther than the original spindles. Is that correct? I was going to do this swap with my 66 but I don't want to shorten my wheelbase. Thanks for answers in advance.
What you read was incorrect.
The Granada spindles do NOT change the wheel spacing. Or, in other words the backspacing on your rims will not need to be altered. However, as an example Wilwood brakes DO have a 1" wider positioning and would require new rims with additional backspacing to properly fit.
Granada spindles in my 70 mustang - work PERFECT - just use the right ball joints and tie rod ends as the chamfer is different - the spindle is thicker too (stronger than the 69 and earlier units - much like the Boss version) Cheap to get new rotors, pads, bearings, calipers, etc... from the local parts store too.... I did the 1.5 inch drop on the upper control arm at the same time and put a homemade wedge between the upper ball joint and the upper control arm to set it in the middle again - car handles like it is on rails - highly recommend - also heavy front and rear sway bars installed....