4 hours- if u don't have any probs like seized/rounded bolts etc. If u gotta replace other bits, flush and refill coolant, then check over everything uve done I'd say allow a day realistically. My 9a went in real easy, when I put the abf in for some reason the three bolts for rear engine mount were a pig to align up,only slightly out, this prob took half hour alone, so 4 hours maybe in a perfect world...