Run Normal Gem as an item.
EVs: 12 HP, 252 ATK, 244 Speed
Now this is a VERY standard set, but it't standard for a reason. There are several pokemon that are great to think outside of the box with, Gigalith without sand isn't one of them.
Either way with this you'll still have decent bulk, but you'll be able to set up rocks, get some KOs if typing plays out right, then Explode in something's face.
Brick Break isn't doing you too much good. Plus, you're going to take some serious damage when setting up Nasty Plot on something as frail as Raichu. Take away Life orb for Expert Belt since you have Bolt-beam coverage. This will make him last better. Focus Blast > Brick Break to keep the set special.
252 HP / 252 SP Def / 4 SP ATK has worked better in my use.
I also suggest Sludge Bomb over Flamethrower. " Sludge Bomb grants Weezing a STAB move in case it needs to attack. While it won't be that powerful, it can be nice to kill weakened switch-ins such as Magmortar and Exeggutor. " - Smogon
A smart quote that I fully agree with. Clear Smog isn't an attacking move as much as it is a supporting move.
Charge Beam over Calm Mind. Use it to finish off an opponent's pokemon and get that Special attack boost. Alakazam is pretty frail to try setting up Calm Mind. Kadabra is WAY too frail to try setting up Calm Mind ( assuming there's no gimmicky eviolite involved )
Run Torrent as an ability. Replace Night Slash with Waterfall. Double STAB is fine when you have priority, and is essential for Samurott. He can't hit too hard with Aqua Jet most of the time. Use 112 HP / 252 ATK / 144 Speed as an EV spread. You'll find it balances out well.
Run Eviolite. Being locked into a move doesn't fit Machoke very well, and he needs the extra bulk considering he isn't going to be out speeding anything.
Move choices really vary with taste, but you should be good there.