I think you keep missing what is being said to describe the connecting rods. All GMC rods, regardless of what cubic inch they came out of will fit onto any GMC crankshaft. The width of the bearing tang, the bent portion of the bearing that fits into the notches in the rod and rod cap are what is different. There are numerous rods that have the same forging numbers but can have either size of bearing tang widths and also different wrist pin sizes, so you have to measure both the tang widths and wrist pin size on the rods you have to get the correct pistons and correct bearings. So when it comes to GMC and their forging numbers, the forging numbers are almost irrelevant because so many of them can have both style of bearing tangs and either size wrist pins....Hope that helps!
