My 58 Chevy 1/2 ton handles a trailer with brakes just fine. Course it has the 261 in it now with the three on the tree, but I have towed with the 235. It wouldn't run 90 down the road with the load, but as long as it was balanced correctly and brakes work on the trailer, it will tow okay.
Get the load too far forward and it will road walk. It will make the 235 work for it, but it will tow the Mustang on a good trailer.
