I always try to install springs at the manufacturers recommended height, and the rule of thumb that I have always used is to have at least .060 clearance for coil bind. If you are installing these springs at 1.650 with a .495 cam it seems that you have about .030 of coil bind clearance, to me that is too little. Now, others may disagree, but I would do as a previous poster said and get some .050 taller retainers or locks and shim the springs to the suggested 1.700 installed height.