No to your impression - they put 360's in everything starting in 1971 C-body's liked them and yes A bodies do have a different pan for that center steering link.
The correct oil pan should be the first - they did make a 360 pan for the A body and yes a little rare but they are around - correct early V/8 mounts and shouldn't have an issue with the stock 64-66 linc.....BUT if your up grading brakes you'll need all that steering from outter tie rod to...
My 1st 1965 Formula S I looked at in 1974 and eventually bought about 1976 had a 4sp and 8 3/4 - I still have the fender tag along with a lot of the parts from it - it had the side swiped as it sat out on the street. My current 1965 S 4 sp is a Feb build with a 7 1/4 posi. Parted a 1966 auto S...
Sadly one reason I got rid of my matching # 1968 Formula S as a roller - could not fine quarter panels in the 80's and my right side was caved in from bumper to door.