For a little bit of backstory, I really like the original 150 pokemon as opposed to the new ones. As a result, I have decided to attempt to create a competitive team that uses only the originals, in an effort to prove that they are still competitively viable.
So, without further ado:
AERODACTYL @ Choice Band (lead)
Ability: Rock Head
EVs: 252 Atk/252 Spd
Basically, this thing is designed to KO the opponent's lead. CB gives it enough power to do just that, and Aerodactyl has pretty insane speed. I chose Rock Slide over Stone Edge for the Accuracy, since Aerodactyl can't exactly afford to take hits.
GYARADOS @ Leftovers
EVs: 152 HP/176 ATK/36 DEF/144 Spd
Gyarados, the king of the Sweepers...used for bulk?! What is this blasphemy (other than a great nickname?) It is going to be used to wall things like Garchomp and T-Tar, that desperately need their Attack reduced. Not to mention, the fact that a lot of people will probably switch out against it lets it get a free DD. This set has so much potential, I love it.
CHANSEY @ Evolite
Ability: Natural Cure
EVs: 6 HP/252 DEF/252 Sp. Def
Chansey: It's pretty much the standard Special wall of this generation, especially with Evolite. Toxic will let me spread the poison around. Unfortunately, I have no way of giving it Wish, so Charm will have to do in its place. Seismic Toss is probably the most damaging attack Chansey can use outside of Toxic. Softboiled is for recovery.
MACHAMP @ Lum Berry
Ability: No Guard
EVs: 252 Atk/252 HP/252 Spd
Basically, it's coverage for T-Tar and Chansey. I chose to run Bulk Up over Payback due to the increasing proliferation of Trick Room in the metagame. That, and I'm probably over-valuing bulk.
GENGAR @ Life Orb
EVs: 4 HP/252 SAtk/252 Spd
Basically, this thing is my special Sweeper. It's incredibly fast, immune to EQ, and has a great movepool. STAB-ed Shadow Ball gets it on to this team over Alakazam, and Thunderbolt is there to stop Skarm. Explosion isn't all that bad as a last resort attack, either.
DRAGONITE @ Choice Scarf
Ability: Inner Focus
EVs: 4 HP/252 ATK/252 Spd
It's Dragonite. By no means is it a bad pokemon, however, it is definitely overshadowed by Salamence (which is unavailable, given that this team only uses Gen 1's.) It wouldn't be that bad if it weren't a giant fatty that needs Choice Scarf to get any speed. Fire Punch lets it take out Ferrothorn and Metagross, Earthquake takes out a bunch of stuff, STABed Outrage gets rid of Mence and Chomp, and Aqua Tail gets rid of all those pesky ground types.