LA Small block valve size?

Does anyone know what the origonal 2.02 valve lengths are? I'm getting conflicting results but reason I'm asking is I have a set that I want to put in my 360 heads while they are in for valve guide work. The # i come up with by just a digital caliper is 4.973" in over all length but maybe I need a better way of determining the length as hard to get a square to valve reading. Any ideas out there? Thanks

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