Standard TormentTran's Lava Plume vs. 4 HP/0 Sp. DEF Occa Scizor: 95.7% - 112.8%
Standard TormentTran's Lava Plume vs. 252 HP/4 Sp. DEF Occa Scizor: 77.3% - 91.3%
Standard TormentTran's Lava Plume vs. 252 HP/252 Sp. DEF Occa Scizor: 59.3% - 69.8%
Average 1HKO on even max HP Scizor with Lava Plume.
If you run max HP/Sp. DEF Occa Scizor to survive...
+2 4 ATK EV Adamant Occa Scizor's Brick Break vs. TormentTran: 73.4% - 87%
You fail to 1HKO even with Rocks down(85.4% - 99% after Rocks). You could pump more ATK EVs, but even then your chances of 1HKOing are unlikely to be over 50% while surviving.
None of this takes into account burn chance from Lava Plume, prior damage on Scizor/Heatran or the more powerful Flamethrower(Flamethrower from just TormentTran's EVs, which would be lower than normal for any set running Flamethrower, is 69.8% - 82.6%, so you won't survive...).
Basically, you don't win against Heatran.
NP MixApe does 91.3% - 108.1% to 252 HP/252 Sp. DEF Adamant Scizor, as does Specially-Based MixApe. Physical MixApe does 115.1% - 136% with Overheat. Fire Blast on any MixApe is 115.7% - 136.6%, a guarenteed 1HKO even with max HP/Sp. DEF
Occa Scizor doesn't beat either. Even if we give Scizor a Careful nature, MixApe's Flamethrower does 83.7% - 99.4%, a very high chance of OHKO after Rocks.
Note that Scizor can only do 29.9% - 35.4%, 67% - 78.9% or 40.1% - 47.3% with it's moves after a SD, meaning you must use Brick Break + Bullet Punch to KO it. With Careful, Infernape actually has a low chance to survive Break + BP.
Note that none of this takes into account that Fire Blast is the main option on both Heatran and Infernape. 62.1% of Heatran in April ran Fire Blast, although Infernape numbers were significantly lower(39.9%). Again, though, Flamethrower still KOs you. Even Flare Blitz, used 15.3% of the time, does 127.3% - 150% after Occa on physical MixApe to 252 HP/0 DEF Scizor. Even Flare Blitz from SPECIAL MixApe does 108.1% - 127.3%.
Occa Scizor doesn't work against Heatran or Infernape.
Standard TormentTran's Lava Plume vs. 252 HP/4 Sp. DEF Occa Scizor: 77.3% - 91.3%
Standard TormentTran's Lava Plume vs. 252 HP/252 Sp. DEF Occa Scizor: 59.3% - 69.8%
Average 1HKO on even max HP Scizor with Lava Plume.
If you run max HP/Sp. DEF Occa Scizor to survive...
+2 4 ATK EV Adamant Occa Scizor's Brick Break vs. TormentTran: 73.4% - 87%
You fail to 1HKO even with Rocks down(85.4% - 99% after Rocks). You could pump more ATK EVs, but even then your chances of 1HKOing are unlikely to be over 50% while surviving.
None of this takes into account burn chance from Lava Plume, prior damage on Scizor/Heatran or the more powerful Flamethrower(Flamethrower from just TormentTran's EVs, which would be lower than normal for any set running Flamethrower, is 69.8% - 82.6%, so you won't survive...).
Basically, you don't win against Heatran.
NP MixApe does 91.3% - 108.1% to 252 HP/252 Sp. DEF Adamant Scizor, as does Specially-Based MixApe. Physical MixApe does 115.1% - 136% with Overheat. Fire Blast on any MixApe is 115.7% - 136.6%, a guarenteed 1HKO even with max HP/Sp. DEF
Occa Scizor doesn't beat either. Even if we give Scizor a Careful nature, MixApe's Flamethrower does 83.7% - 99.4%, a very high chance of OHKO after Rocks.
Note that Scizor can only do 29.9% - 35.4%, 67% - 78.9% or 40.1% - 47.3% with it's moves after a SD, meaning you must use Brick Break + Bullet Punch to KO it. With Careful, Infernape actually has a low chance to survive Break + BP.
Note that none of this takes into account that Fire Blast is the main option on both Heatran and Infernape. 62.1% of Heatran in April ran Fire Blast, although Infernape numbers were significantly lower(39.9%). Again, though, Flamethrower still KOs you. Even Flare Blitz, used 15.3% of the time, does 127.3% - 150% after Occa on physical MixApe to 252 HP/0 DEF Scizor. Even Flare Blitz from SPECIAL MixApe does 108.1% - 127.3%.
Occa Scizor doesn't work against Heatran or Infernape.