Boyle,
In answer to you original question. Any oil will work well in your recently rebuilt engine that has already been broken in.
Almost all oils are made to the same specifications. Obviously, hot/cold viscosities differ and there are differences between gasoline engine oils and diesel engine oils - differences that are probably of minimal import for light truck engines.
Increased levels of ZDDP are only needed during break-in of a new cam and flat tappets (as would be the case in old GM straight six truck engines).
