1. They are all 28 spline. (or in some cases 31 for the hi HP cars )
2. it is the same (functional) length but the end is longer to accommodate the disc brake
3. it's up to you
4. You will be getting front spindles, rotors and calipers for either the sn95 or the lincoln 5 lug swap. The issue with the lincoln/granada swap is that you have to watch the center opening on the wheel because the spindle on those stick out longer. So if it's a comp car no problem, if it's a show car you may need to make sure the wheel center cap will fit

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