I had a V code 1970 Charger R/T 4 speed car bought new in Victorville, CA in November of 1969 by the original owner.
I ended up becoming the 3rd or 4th owner of it in 1the spring of 1989 with the car being bought taken apart and missing the original Dana 60, 4 speed console six pack set up and the original block, the original owner had the short block replaced in the early spring of 1970. It had a SPD of 10-28-1969 under warrenty for some unknown reason .
I ended buying a late production 1969 dana 60 out of a 1969 Charger R/T and I was lucky enough to buy two different 1970 cast iron six pack set ups, one with non CA six pack carbs for the manual trannies and one CA set up for the automatic CA cars.
One of the cast iron intakes had a casting date of 10-21-1969 and the other one had a casting date of 10-28-1969 so that makes me think that Mopar switch to the cast iron 6 pack intakes in the early production run of the 1970 cars IHTHs