I think what you might have there is the AC section cut from the radio console of a 1968 Thunderbird or similar.
There was not a lot of Brit cars with AC at the time so I think it came from a Fomoco US parts bin.
Shelby Mustangs had similar grilles at the time but there is no push pull air volume knobs that I can see on those so I suspect that they might be on the quadrant.
P1028 has an FAV Slough fitted Smiths road car heater fitted on the scuttle and there is a secondary Smiths fan and plenum fitted in the footwell for the AC unit. There is a whole lot of weight in the FAV heater and plenum box. I can weigh my one if you want but it is probably much the same as the modern SPF AC workings.
I presume that they upgraded the original Alternator to cope with the extra amps at the time.