Legendary Pokémon

Ninjask
@Leftovers
Speed Boost
-Substitute
-Baton Pass
-Swords Dance
-X-Scissor

Marowak
@Thick Club
Rock Head
252 Attack/ 252 Speed
-Earthquake
-Rock Slide
-Double Edge
-Fire Punch

Alakazam
@Choice Specs
Synchronize
252 Sp Attack/ 252 Speed
-Psychic
-Focus Blast
-Energy Ball
-Trick

Salamence
@???? Item suggestion?
Intimidate
252 Speed/ 144 Sp Attack/ 108 Attack
-Dragon Claw
-Draco Meteor
-Brick Break
-Flamethrower

Bronzong
@Wide Lens
Levitate
-Hypnosis
-Dream Eater
-Earthquake
-Gyro Ball

Snorlax
@Leftovers
Immunity
-Curse
-Earthquake
-Body Slam
-Explosion

For my strategy I will send out Ninjask and get speed boosts and then Baton Pass to Marowak@Thick Club. Hopefully he will be able to hit first with an attack near to 500. If Marowak falls (hopefully he goes down with a few of my opponent's) then i Will send out Alakazam. With Choice Specs his Sp Attack will be outmatched and I will sweep his team. If my opponent switches into something I can't take down, I can resort to switching into Bronzong or Snorlax who can take a few hits. Then I can switch back into Alakazam possibly after an Explosion. My Salamence will function as a late game Sweeper to end it if needed. Comments.. Suggestions.. Either will help.

As for Salamence,you should replace draco meteor with something else because you already have two dragon-type moves.(just for type coverage).
Snorlax could be easily blocked by Skarmories and steel types that have the ability of levitate(or that can have this ability using magnet rise).I would also replace leftovers with quick claw since Snorlax doesn't have any problems with its defences and hp but is slow.(you can use silk scarf for boosting explosion,too)
Oh,i almost forgot,boosting items are not much trustable but,putting dragon fang on Salamence would be a nice idea.(although,you need to put some ev points at its defences).
I don't know much about natures but,post them,maybe other guys help you.

well i'd suggest you to remove choise specs from Alakazam beacause you have and Trick and it wouldn't give you advantage switching all the time. Give Alakazam life orb. Next Salamence's item... Here choise specs is suitable and instead of draco meteor hydro pump will be ok

Your team is not bad, but it need a few changes.

Firstly, Ninjask should be taught protect instead of Substitute, for if you do not have enough HP after an SD, you will be force to Baton Pass. Also, give Ninjask the Focus Sash so that it will have the time to pull off 1 SD and 2 Speed Boosts.

Marowak is fine.

Alakazam is fine.

For Salamnce, you should give it the Life Orb. You will lose HP as you use it, but it gives a 30% boost to all moves. You should also make it forget Dragon Claw or Draco Meteor and replace it with a different move, like Hydro Pump.

You should also give Bronzong Leftovers. I understand that you are trying to make Hypnosis more accurate, but the boost is so little, it will not matter much. Also, if you run across an opponent you cannot put to Sleep, you will be left without a way to recover off Damage.
Snorlax is fine.

I am hoping Bronzong is a Special wall, as Snorlax is meant to take Physical hits.

Overall, it is a decent team. I would rate it a 7 out of 10.

Well, it's a nice team, but as the others said, it needs a few changes. First of all I think that substitute is far better than protect, since it gives you more safety and you can also BP, so that the next pokemon won't be instantly KOed.So I disagree with ExplorersAce opinion. You could also teach both protect(instead of X-Scissor) and substitute to ninjask, if you want larger boosts and don't plan to attack with it.
I agree with George7 and believe that you should change choice specs in alakazam, because trick in that case won't be any help at all.
Also, due to the fact that bronzong is mainly a defensive pokemon, I don't know whether its earthquake will do much damage. Better put explosion instead of it.
The rest is ok, although I'm surprised to see a snorlax with explosion.

ninjask is crap........ use a heracross