Your 62 has that inline trans filter making it a bit tight down there. My 66 has power steering . I took it to the muffler shop and had them make a 2 1/4" head pipe and exhaust system . They used a muffler that gave it just a bit of back pressure. It really woke the car up on the freeway almost like a V8 .
We did a later Duster without any back pressure and it fell on its face, so we changed the muffler to give it a bit of BP and it woke up.