ORIGINAL: 46u
Boy try to find a good tire that with handle all those well!!!!!!! I would stick with packed dirt.
I don't know about them, but Pro-Line Mashers look pretty verstile as far as what surfaces because of the treads. However, since he's going with dirt, I guess it doesn't really matter. Are you going to be racing a stock Savage, or are you going to lower it and modify it for dirt?? Some good jumps would be great for your track. Hope it turns out well for you.