[dsraven]

LG, good info. my truck was a 63 GMC and it had an inline 6 and 3 on the tree originally. somewhere along the way somebody upgraded to a 283 with a hurst floor shifter on the original non syncro 3 spd. I found the floor shifter a pain because it was a short handle so it was at about the height of the bench seat. it had trailing arm suspension with drums all around. I used it as a daily driver and used to haul sleds, dirt bikes, dunebuggies, bicycles and firewood (as a kid we heated our house with an antique wood furnace in the basement and I was the wood guy). My tryck had an 8 ft box and I used to cut 10 ft lengths of wood and stack it in the box as high as the cab roof, then drive DOWN the mountain in the shuswap area of B.C. yeah, I know what brake fade is, lol. anyway, the point is the old truck had the guts to do that with the Moog variable rate springs installed, and it rode pretty well on the road normally with no load. it cruised down the highway at 60 mph but that was wrung out like a wet sponge if I remember correctly. don't know what axle ratio it had. it would do a burn out if pushed, hard, lol.
thats why I suggest to figure out what the driving conditions will be and then figure out what axle ratio and trans ratio's will result in the best fit for the old 6.