My opinion would be the c6 is a good tranny BUT if you are gonna run an automatic YOU MUST run a big cooler for it...also if you are not running an overdrive, or changing the axle gears, to bring the RPM's down, its gonna be a fairly harsh environment for an auto...make sure the cooler is as big as possible basically...either a manual or auto would work...a manual with a granny low would give the best crawl ratio, if that would be needed...sounds like your looking for faster acceleration though, mud, and there the auto may have some advantages.
On the motor mounts, I dont know if the 351 M will fit the 351 W mount, but you can get a 302 mount from JC Whitney and I think Advanced Adapters...the 351W will bolt into that mount...done that in cars, no differences...so if the M types mount is the same, you got it...I just wouldnt hold my breath though....it would make it an easy swap though.
Good luck and keep us informed...sounds interesting to me!!
brute4c
Lord send your Holy Ghost into our hearts and make the desire of our hearts Your Will.
Pro-choice, that's a LIE, babies don't choose to die!!