Your question "Could you tell us where to look please." was a little confusing when you highlighted "a lot of people" and " I think you should look elsewhere". I'm sorry I can't read your brain... Thought you were asking about how I was suggesting that the problem might be engine or engine management related and not gearing.
Vincent, I assume you've slid your NA 240 around before. On gravel and pavement, yes? How difficult was it? Can you do it in a gear higher than 2nd?
I've drifted a NA volvo 240 before. I'm not the first, I'm not the last. I've also drifted a turbo 240, and now I drift a 240 with a v8 in it. Once again, not the first to do it, or the last.
The fact that the OP is having "bogging" issues that are very poorly described leads me to think that there are more issues than just gearing here. I could take off without issue in my old turbo car using 2nd gear with a 6-puck ceramic clutch, without any bogging or drama.