I too have been watching these A Body Darts on the rise the last couple years.
A very nice (numbers and original panels) 69 or 70 340 Swinger will now easily bring upper 30's.
4 Speeds more.
The ones I see in the mid 40's seem to be for sale by dealers and they typically sit unsold.
I think the days of buying a nice Swinger 340 in the mid 20's are gone.
I agree the rising E and B body's have pulled up the A's with them.