I like Ravix's suggestion, but if you're going to replace Hydreigon with Salamence, make him a
Physical Attacker. His base 135 Attack stat dominates over his base 110 SpA stat, making it a better choice for him to be Physical-based. Plus, it adds another Physical Attacker next to Hitmontop; you have enough Special Attackers.
Salamence - Physical Attacker

Salamence @ Life Orb | Intimidate
Jolly Nature (+Spe, -SpA) | 4 HP / 252 Atk / 252 Spe
Dragon Claw / Earthquake
or Fire Fang / Crunch / Tailwind
STAB Dragon Claw + Life Orb OHKO's the likes of Latios (139.7% - 166.7%: 100% chance to KO) and Garchomp (104.3% - 123.9%: 100% chance to KO). Earthquake is for coverage against Metagross, Excadrill, Tyranitar, etc. Fire Fang is also a good choice for coverage against Ice-type threats such as Max HP Abomasnow and Glaceon. Crunch OHKO's Gengar (135.3% - 160.3%: 100% chance to KO) and 2HKO's Max HP Cresselia (45.8% - 54.6%: 4% chance to KO). Tailwind lets you outspeed any other Pokémon not in Tailwind, which is a great advantage to its Dragon-type rivals. Here's an easy list to read of all the calcs I did:
Salamence w/ Life Orb vs. Threats
Latios: Dragon Claw - (139.7% - 166.7%: 100% chance to KO)
OHKO
Garchomp: Dragon Claw - (104.3% - 123.9%: 100% chance to KO)
OHKO
Abomasnow: Fire Fang - (127.9% - 152.3%: 100% chance to KO)
OHKO
Glaceon: Fire Fang - (65.7% - 78.6%: 6% chance to KO)
2HKO
Gengar: Crunch - (135.3% - 160.3%: 100% chance to KO)
OHKO
Cresselia: Crunch - (45.8% - 54.6%: 4% chance to KO)
2HKO
As you can see, with his amazing movepool, Salamence can either OHKO or 2HKO most threats. But you have to make sure he doesn't get OHKO'ed the first turn against these threats. This set can be effective, but you have to know how to use it. Maybe a Fake Out Attacker + Salamence will help. Most preferably
Hitmontop + Salamence for that double Intimidate combo. Or give Salamence a
Focus Sash to guarantee Tailwind setup. Hope I helped, bro!