Below are the W engine shipments to the plants, CONV is 3 or 4 speed, others auto trans, Powerglide and Turboglide.
Interesting to note they mixed some RPO code shipments, ie, look at RPO codes 573A is a 280 HP with 3x2’s and 576 is 250HP single 4bbl, combined for 5350 of those. Also a 573E HLC(high lift cam) is a 335 HP with 3x2’s and once again mixed with 576.(no A listings)
Not sure if this helps but it’s about as close as it can come without a better RPO code chart.
At least these are the combinations shipped.