[COPO]

I've done limited research on this. The MSO's that I looked at do not appear consistent as I came across at least two examples of MSO's w/48.0 Taxable HP which indicates a 350 and cars both had original buildsheets indicating they were LS-6 coupes. Perhaps if there was a large sample size from various plants a pattern would emerge. The MSO's seem to be a rare document.