The number available is the sales percentage for the previous year based on model.
The problem is it can get skewed easily. For example the number of 70 'cudas that are painted FM3 is very, very small. Yet if you looked at AAR 'cudas the percentage would be much higher.
Your best bet is to ask what data that Dan might have.
these numbers account for ~87% of 1970 'cuda BS23/BS27 production - the only "by engine" numbers would be "known" per someone's collected info/registry
arranged by least common to most popular Mopar musclecar color