As long as you use the correct cam sprocket, the retainer plate won't pose a problem. If I remember it correctly, the sprocket used with the retainer plate has a stepped-down section that fits through the retainer and sets the proper cam position and end play. Before that feature was added to the small block engine, we had to fit a thrust button between the cam and the timing cover when we used a double-roller timing chain to keep the cam from "walking" back and forth and changing the ignition timing. I always brazed a heavy washer onto the outside of the timing cover to keep it from flexing and cracking the sheet metal. The thrust plate solved that problem.
Jerry
