There's a huge chance if Goku could got a 33x Zenkai after the clash with Captain Ginyu, for Bardock such a huge near-death experience could generated similar boosts. So if Bardock was at 3000 before the clash with Freeza then he could grew to 100.000 units which could be enough for a Super Saiyan transformation.He said his heart was calm and still, still and pure, pure evil. That would be referring to his heart. Like I said anyway it doesn't really all add up if you went by the assumption that Bardock's power level was the very high level that was required to become a Super Saiyan.
1. When they say a very high power level that would be for a saiyan. Bardock does not have a very high power level, it could be less than 2,000. It's only at the high end (above average) for the low class, the weakest of the lot.
2. It's hard to believe that with such a low requirement not one other saiyan achieved the form in hundreds upon hundreds of years.
3. Vegeta was never able to become a Super Saiyan before when he got mad and I don't believe for a second that his time on Earth caused his heart to change to an extent that it later became possible for him to become one because he was still a scumbag.
4. Goku never became a Super Saiyan when he found all his friends dead unlike Future Trunks did when he saw Gohan dead. Nor did he transform at any point during the battle when he was losing, the Earth was in danger or him seeing his friends hurt.
5. Gohan who has the purest heart of the lot never became a Super Saiyan when he thought Krillin died or when Piccolo was being hurt. His power level shot up a vast amount but that was it.
The only logical conclusion is that when they say a very high power level, they're talking in the few millions and not thousands. In which case it would only really make sense that Bardock had a huge zenkai boost following Freeza and that was why he transformed.
But then that wouldn't make sense with Bardock being a low class or Chilled not being abnormally strong.
So the whole thing just doesn't fit at all.
Hmm... you do have a point. I guess then that Toriyama isn't acknowledging EoB. Which would mean that if EoB happened in the manga continuity, Bardock got a big near-death power-up that made him between 30.000 & 60.000, which is when he would be above the standard Saiyan level.
But if that happened it's strange that Toriyama keeps Bardock the Low-class range. The most sure case is Bardock did not have any distant past experiences.
This is Toriyama's answer for Bardock's power level:
Maybe Toriyama didn't expect to be asked about Bardock's level, so he shared his original thoughts about Bardock's power, and may be he didn't concentrate on Episode of Bardock.About how high was Bardock’s battle power, ultimately? (In Episode of Bardock) Also, if he hadn’t been defeated by Freeza and had continued his growth, about how strong would he have gotten?
To be honest, I haven’t thought it through that far, but Bardock is a low-class warrior. Although even saying that, almost all [Saiyans] were low-class warriors, and there were only about 10 mid-class warriors. And when you get to the elite warriors, there’s only King Vegeta and Prince Vegeta. Bardock is in the upper ranks as far as low-class warriors go, but he isn’t able to become a mid-class warrior.
This rank is determined by an innate latent battle power, but naturally, if their battle power rises greatly afterward, they can be promoted.

