As Mongo as indicated, there are some things one has to do to make a military engine fit in a civie car or truck. They are not insurmountable by any means. The military mounting is removed/tossed and you use the area for the standard civilian application already there. Also as indicated, look behind the distributor area for a number. If there is a 302, 270, 248, 228 anywhere there, then it will fit in a GMC truck with few problems. These numbers also denote the cubic inches of the engine. GMC made other engines but I have not seen or worked with them to add or detract from the availablility of them being able to work in the trucks. Maybe someone else can throw in here. Any news yet on the sizes you have come across? How about the prices?
