Here are a couple of places for info and parts.
460 Ford Forums.
Everything you ever wanted to know about the big block ford. 460's were externally balanced starting in 1979 like insane said.
L & L Products.
They have everything you need to do a 460 conversion. They are a little pricy for some things though.
I may be wrong, but I think you may be able to use a oilpan and pickup from an 80's or 90's truck with the 460. I think they are the same as the one L & L sells. Oh, and don't forget the main bolt with the stud to mount the pickup. You don't need to change the mount towers if you have a 351M and use the L & L mounts either.