Bob.
I also had 40" Cepek Fun Countrys and Monster Mudders on my 78 Dodge.
But as I recall, they were only a C rated tire, (15" rims).
Plus a non-radial. Were like 4 square tires in the winter for the first few miles.
I have been running the FC-II's for about 2 years now.
Made by Mickey Thompson, and a heavy weight range.
I would honestly say these are the best tires I ever owned.
But I always run a large tire, and every truck has been lifted.
They are smooth riding, and not very noisy for the tread design.
Great in snow, wet roads, loose dirt, and packed mud.
Haven't been in soft soupy deep mud yet.
Wear is excellent, and no cupping. Really like them.
Brad