How hard is it to change 170 motor mounts?

Make sure to loosen up the opposite motor mount. I use a 2X4 across the bottom of the oil pan so as not to bend it out of shape. New mounts are available both in cheap and expensive models (even Poly).
Don't buy a remanufactured Distributor they just aren't worth the headaches. Maybe its time to convert to HEI or EI.
Frank