Hello, I'm on the process in rebuilding my 58 841 diesel and right now I'm trying to get the motor back together. I'm rebuilding it all. A complete rebuild kit, new crank, bearing and gaskets. Anyway, on to my question, the head was messed up so I bought a good used one and was in the process of taking the valves out to replace them and that's when I noticed that all the valve guides where the same. Now according to what I read and parts I received, it looks like on diesel models the intake and exhaust valve guides are different vs gas motors used the same guide for both intake and exhaust . What was the reason they used different guides for a diesel motor? Can I just leave the guides in there or is it necessary to change out the intake guides to the proper ones? Thanks.