Kitbashing Thousand Sons with other Space Marine torso bits?

[Lay]

Hey all, I have a question for those who have the plastic Thousand Sons kit.
 
So, due to the never ending scale creep, the newish plastic Thousand Sons are notably larger than many of the older Marine models:
1. https://imgur.com/a/gq0ZE#LGpVRJu]https://imgur.com/a/gq0ZE#LGpVRJu
2. https://uploads.disquscdn.com/images/6996a0295e760777dddd6ec6efb8916853b16df89e8139ccf52eb2ed24bc0b7a.jpg
3. https://images.dakkadakka.com/gallery/2017/2/13/856847_md-Thousand%20Sons%20size%20difference.jpg

I really like that they don't look so pathetically stunted next to Primaris Marines. It makes me want to use them as a base for larger Undivided Chaos Marines.

 

Now, I want to go beyond a simple headswap and exchange some other bits, particularly the torsos which look very Tzeentchian. I'm just not sure if the size difference is just a result of different leg poses or if the Thousand Sons are overall bigger.

Basically, is it possible to replace these torsos with other Power Armor torsos, like Forge World's Legion upgrade sets or the Chaos Raptor ones without losing any height?

Thanks in advance.