I have a Question...
Couldn't Heatran also work well with Dragonite/Salamence?
Roost/Sunny Day/Dragon Pulse/Fire Blast?
Roost isn't affected by Weather changes, Takes off Ice Weaknesses, and heals like Synthesis.
Sunny Day Boosts Salamence's Fire Blast (off the same Special Attack as Tangrowth), and helps Heatran, and since Salamence is Naturally fast it doesn't need the Chlorophyll boost to outspeed alot of pokemon.
Salamence also provides the same resistances as Tangrowth does for Heatran, except even better: Immune to Eq/Resistant to Fighting/Resistant to Water.
In Addition, he gets the Fire/Dragon Combo, and with Sunny Day it gets a Pseudo-Stab.
Dragon Pulse also subsitutes the need for Hp Ice (except for Gliscor), as 135 Base (After STAB) is 270 Base Power when super-effective vs other Dragons, only 10 less than a 4x Super Effective HP Ice.
In addition, Salamence gets the option of Wish, which especially comes in handy when your Heatran is holding Life Orb.
Also, when you switch to Salamence, Intimidate activates.
Dragonite can pull off the same set, but has less speed and Special attack, and doesn't get Wish/Intimidate, but does recieve better HP/Defenses.
And lets face it, Heatran resists Salamences' weaknesses: Ice/Dragon, and takes neutral from Rock (but factor in Intimidate). Perhaps this may even deserve its own MenceTran thread...