Doesn't Exeggutor complement Heatran better than Tangrowth?

[Akatsuki]

Um... as requested, EV spreads and some calculations.
Heatran @ Choice Scarf
Modest Nature (+ Sp. Atk, - Atk)
EVs: 252 Sp. Atk / 252 Spd / 4 HP
- Fire Blast
- Solarbeam
- Dragon Pulse
- Earth Power

This is just basically your good ol' standard Scarftran except the addition of Solarbeam. That will help it hit bulky Waters if you can predict them switching in.

Exeggutor @ Leftovers
Naïve Nature (+Spd,-Sp.Def)
EVs: 212 HP / 100 Atk / 120 Spd / 76 Sp. Atk
- Hidden Power Fire
- Energy Ball
- Sunny Day
- Explosion

Ok, let me explain the EVs:
212 HP produces 384 HP, which allows to a nice Leftovers recovery. 100 Atk EVs is the minimal amount of EVs required to OHKO a standard Blissey (148 HP, 252 Defense, Bold Nature), which will do 100.73% - 118.46%. 120 Speed EVs with a Naïve Nature will produce 192 Speed, which after Sunny Day activates Chlorophyll, will reach 384 and will outspeed Jolly Weaviles and Swellows by one point. The remainder went into Sp. Atk.

Here's some damage calculations done: (using Metalkid's Calculator)

Explosion on 148 HP / 252 Def + Bold Nature'd Blissey: 100.73% - 118.46%

Hidden Power Fire on 4 HP Gengar (with Sunny Day active): 47.71% - 56.49%

Hidden Power Fire on 4 HP Weavile (after Sunny Day is active): 79.79% - 93.97% (OHKO with Stealth Rocks up)

Hidden Power Fire on 252 HP Forretress (after Sunny Day is active): 167.51% - 197.18%

Hidden Power Fire on 252 HP Forretress (if Sunny Day is NOT active): 112.43% - 132.20%

Hidden Power Fire on 4 HP Heracross (If Sunny Day is active): 68.54% - 80.79% (Be careful, in Sunny Day Exeggutor STILL does NOT outspeed Adamant Scarfcrosses)

Energy Ball on 60 HP Tyranitar (during Sandstorm): 63.76% - 75.00%

Energy Ball on 172 HP Starmie: 85.20% - 100.00% (OHKO most of the time if Stealth Rocks is active)

Energy Ball on 252 HP Suicune: 50.00% - 58.66% (Definite 2HKO with Stealth Rocks up)

Explosion on BulkyGyara (212 HP / 180 Def): 65.89% - 77.60% AFTER Intimidate

Explosion on BulkyGyara (212 HP / 180 Def): 98.44% - 115.89% WITHOUT Intimidate

Explosion on Togekiss (252 HP and 4 Def, which is what Smogon recommends): 106.42% - 125.13%

This is what I use.

 

[Beat]

Other than that, I like Tangrowth a lot because he's got better physical attack, better defense, and a kick-awesome STAB move (Power Whip), on which no other Pokemon has STAB.

You forgot Carnivine. Not that it even comes close to Tangrowth.

 

[obi]

Celebi isn't broken by Surf + Ice Beam. Pokemon using that combo are, as a rule, Water types, meaning they don't have STAB on Ice Beam (except Walrein and Lapras, and most of them don't have Surf, or if they do, they don't have Blizzard / Ice Beam as well). Celebi's Special Defense and HP paired with Recover mean it's 3HKOed by most Ice Beams, and it can shrug that off with Recover and possibly Leech Seed added into the mix. The only way something is getting through Celebi with Ice Beam is if it's Specs Ice Beam, in which case you can take those with Heatran as long as you predict carefully.

I'd say the main problem with Celebi over other Grass types isn't the Pursuit weakness, but the Crunch weakness, because it means you have trouble with DDTar. CB Stone Edges are also annoying, but I don't think Torterra is worth it.

 

[Bourbon]

Too bad Eggsecutor is mauled by Fire mvoes. The whole point is to get Heatran in on fire. What better bait than A Tangrowth in the sun? (besides parasect in the sun, lol)

EDIT: Oooops, I thought you meant Tangrowth + Eggsecutor, not Heatran and Eggsecutor ._.

 

[chimpact]

Well Eggy is worse IMO because Tangrowth can actually deal with Tar, Crunch OHKO's Eggy, and Pursuit also does lots of damage to it. Tangrowth can Power Whip it and only needs to worry about Ice Beam, but if it does, then it can just switch to heatran. Jumpluff and Shaymin however sound interesting.

 

[TaiwaneseDude]

Why Energy Ball over Solar Beam on Exeggutor? If sun will be up, solar beam is much stronger.

 

[Akatsuki]

Why Energy Ball over Solar Beam on Exeggutor? If sun will be up, solar beam is much stronger.

Well if you r opponent sees that Sunny Day is up, they will probably switch in Tyranitar to change the weather and then Exeggutor will be stuck with a charging Solarbeam while you get Crunched to death.

 

[Amandabynes]

Well if you r opponent sees that Sunny Day is up, they will probably switch in Tyranitar to change the weather and then Exeggutor will be stuck with a charging Solarbeam while you get Crunched to death.

which is why you don't use Exeggutor ...

however i do like the Shaymin idea though i've never used the original Tangrowth + Heatran

 

[Akatsuki]

which is why you don't use Exeggutor ...

however i do like the Shaymin idea though i've never used the original Tangrowth + Heatran

Well I was suggesting it as a possible alternative. Besides, there is the element of surprise.