SAAB V4 1700cc rocker shafts. Note the rocker shaft supports all have round holes and all the bolts have simple thick round washers to cap them off.

SAAB V4 1700cc rocker shafts. Note, one one shaft, both rocker shaft supports have squared off holes. Fluke? I don't know of any reason for this. The squared off holes are so the oil can flow around the bolt. The other shaft has one support with a squared off hole and one with a round one.

SAAB V4 1500cc rocker shafts. Note that each assembly has one rocker shaft support that has a teardrop shape and uses a special washer to cap it off. The hole in the small end of the teardrop allows oil to exit the assembly and drip back onto the cylinder head.

SAAB V4 1500cc rocker shafts. Note square hole in one of the shaft supports on each assembly. The square hole is in the shaft support to allow oil to flow into the assembly.