I mentioned this before about the rocker shaft and I realize you said they went back on the proper "side",, BUT they can be swapped end for end and still be on the proper side. Swapping them end for end MAY put the lube holes on wrong spot. FYI, not all shafts have a notch, some have a 1/2 moon shape and is oriented slightly different.
Double chk that rocker shaft. Most have a notch in one end. If it does, it should be pointed down and to front on drivers side. Down and to rear on pass side.