I am still looking for some needed answers. up to what model year 5.9 mag motor would work for me? My concerns have to do with flex plate balancing and mating to a nuetrally balanced 727 convertor. and my crank pulley bolting to the 5.9 balancer to reuse my v-belt system
thanks in advance
tim

Any 93 to 03 5.9 mag engine will work. You can use a 96 and up flexplate with wieght attached to mate it to your 727. You will have to elongate one of the torque converter bolt holes slightly to bolt it up to your torque converter. The later 5.9s had the pulley cast to the balancer. I believe they stared that around the 2000 M.Y. You can use the earier balancer and LA front cover to use earlier LA v-belt set-up. You will have to modify your brackets slightly from the LA to the Mag tho. The bosses on the front of the cylinder head are not the same height. may be required.