I've been working with it, and
Darvin pretty much hit it on the head. Silvally memories are garbage, and you have to take advantage of what it can really do. This means leaving it Normal, giving it an item, and using his ridiculously powerful STABs, particularly Explosion. Aside from the fact it has Partig Shot, you can always find a better Pokémon that can fo the job and still hold an item.
My personal favorite so far:
Silvally @ Life Orb
Naive Nature
252 Atk / 4 Sp. Atk / 252 Spe
-Parting Shot
-Double-Edge / Return
-Flamethrower / Ice Beam / (filler for your surprise move against the opponent)
-Explosion
This set puts Silvally in what I believe is the best position possible. Fastest speed possible helps it ouspeed threats, and investing in bulk would've either taken from its already meh speed and attack stats. Life Orb helps patch up its meager offenses. Naive allows it to go mixed, and lets it take physical moves better. You could probably go with another item like a Z-Crystal, but the power boost from LO is pretty crucial considering Silvally is hard pressed to hurt things as it is. Maybe Silk Scarf (though now youe coverage move suffers).
Parting Shot helps you pivot if you can't kill something and don't want to Explode yet. Explosion is to break down something you need dead, and also acts as a last ditch effort to hurt something. Double-Edge is stupidly powerful and, while there's recoul with LO wearing you down, it's necessary to make him worthwhile. You can always use Return, though, but there's definitely a noticeable power drop. Finally, that third slot is a surprise move. I enjoy Flamethrower as it roasts the steel-types that try to switch into or resist Normal moves. I don't think he'll be killing Scizor anytime soon (haven't done calcs yet, just guesstimating), but it'll hopefully be enough to dent. I personally think that's the best move for there, but you can use other things like T-Bolt, Ice Beam, etc. depending on what your team needs.