Rear suspension, longer upper links in a 77 Firebird?

[77birdPH]

I don’t really like the short upper links in 4 or 3 link setups. I would want to keep my rear seat, either as it is or replaced it with 2 individual seats. This makes the seat area off limits for a link arm.

For a 3 link the upper link could be on top of the transmission tunnel and it would be like a console between the seats. The link brackets on the pumpkin could be welded direct to the pumpkin not the best idea due to material differences but is anyhow frequently done. What I don’t know is there enough space above the pumpkin; I am very far away from my bird so I can’t check.
I am totally dependent on pictures of what other people have done and Photo bucket is blocked sigh, this reduces the photo material available drastically.

For a 4-link there is a spot above the leaf spring where a box for the upper link could be placed (under kickpanel armrest, see picture)the sub frame would be intact, actually a hole in wheel well only, I think . I am just worried that the area would be weakened. I have a background in off road where everything needs to be reinforced or protected.
I have difficult to understand how the thin materials can hold up. So when enlarging the rear wheel wells some radical cutting is done, have anybody experienced some more flexing or cracking of the structure around this area and wheel wells, when all is put back together and the BB pulls away?



Pictures
Idea for a link-box borrowed from a member here, thanks
Back seat
Back seat out

[77birdPH]

Working for a month now.. got some results, rear 3-link.

Link final version lower links are 22.5 inch long eye to eye.



Basic setup universal coil over kit attachment points turned 90 degrees attached to leaf spring bracket.


Upper link second version 5 inch wide tunnel (first version 3 inch wide could be a problem for upper link touching tunnel walls.)




Upper link bracket welded to diff housing, used stainless welding stick to weld to differential housing. No preheating, the bridge is additional support.


Also installed minitubs to have more space.