about 4 quarts
Yes they should be if not you would only need to modify it slightly.
DOT 3
Haven't had any experience with 66 Fords but would guess it uses ATF fluid. Dextron ll or lll will probably work. Filler cap for PS fluid should indicate proper fluid.
It goes to a bag hanging on the fender wall that holds the washer fluid.
There should be room for a C-4 automatic transmission as I have a '65 and they are the same body style '64-'66 and I have a C-4 with a 302.
44 yrs old
Originally they required ATF type F , though newer technology may allow the use of multi-application fluids, such as synthetic.
As long as the 302 is from a similar year it will bolt right in. The only difference between the 289 and 302 is the 302 has a slightly longer stroke.
yes if you want them replaced
no
There were no Mustangs until '67.
In those years..they used 10w40.