I regularly tow a 3500-pound travel trailer with my 64 New Yorker which
has a similar 413 and transmission to the 59-64 Imperials. It is a
unit-body car, but the trailer place i dealt with constructed a box-type
frame under the rear of the car which seems to work great.
As to brakes, the electric ones on the trailer actually help me stop the
Chrysler better than when the trailer is not connected!
The cooling system required a lot of fussing with and if you get that
far and have troubles, contact me off list. I have some ideas.
Ken Miller
61 and 67 Imperial Convertibles
64 New Yorker Salon