340 xhead spring shimming, height and pocket question(s)

HSDemon said
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.

It's a mechanical cam. Don't forget to add valve lash. Also if coil bind is going to be close I like to measure actual coil bind of the springs. Then the actual lift of the valves with a dial indicator. All this mocked up with the valve springs you are using and on the engine it's going on. I find that actual lift can be less than calculated lift due to deflection and geometry of pushrods and rockers. For me, if it's not close calculating is fine.