coming out of a 57, the engine will have side mounts and use that funky horse shoe mount in the front. In order to bolt this in an earlier 1939-1955.1 gmc truck, the front timing plate needs to be swapped with the earlier style plate. This means you have to pull the valve cover, the rocker assembly, the side cover, the push rods, the lifters, the harmonic ballancer, the oil pan, the timing cover, the distributor, the fuel pump, and the camshaft. After doing all that work, one would have a much better idea of weather or not that engine would require a full rebuild.
John
