If he does not plan this well he could end up with a disaster
1. Every one of these 1J/2j/7m conversions I have seen without planning of XFER case , gearbox, brakes will fail they have been stuck in BMWs, MERCs, 80 series, LAndROVERS, JEEPS, KIA's, rangerovers, LC II's long and short, ISUZU's toyota Corona's and many more
2. Brakes he is going from a vehicle with barely 72kw to something over 200kw (and it will take 500+ with chipping etc) and will do more than 180k depending on his wheel sizes
3. Then he needs to make it handle as he will corner etc faster than normal because it can and he will not be able to resist the urge to bury the foot as it will carve up traffic.