Rear Diff for Hill Climb (Road)

[Urs]

Hello All,

Car is a 2n gen Firebird 455 from 1971. A the moment it has an original, open Diff.
It performs bad. Wheelspin everywhere. Really bad are garages with slope. But the worst thing is what I do like most. Hill climb. Sharp corners, low speed, slope, heavy car, acceleration = problem/no fun.
It is better with very good semi-slick tires, but far from good. On a 2nd car from that period I do not have this problem (no idea whats inside).

So I want to go away from originality an change the diff to a limited slip or a locker. I've read a lot on different diffs. As usual it seems that there is no swiss army knife. So now I'm confused ;)

My personal feeling goes to a Detroit Locker with a very soft spring (40# or even lower if it exists) for several reasons:
- it is appropiate for the time of the car
- I don't care about noise and I like some harsh feeling in old cars. For smooth feeling I have modern cars.
- Lock means lock, every single bit of grip helps up the hill. Especially with quite narrow tires (original size).
- From my point of technical view it seems to be the foolproof variant. Low complexity, low problems.

But my dealer does not like them anymore. He thinks that they do not have the same quality than decades before and they unlock to harsh for street use.
In my opinion there must be a way to overcome those problems. As they are used for som race application, there must be a way to get good parts.

But maybee there are better products for my use case too.

Question:
1st: What would you use today?
2nd: If it is a Detroit Locker, where can I order good quality, blue printed and lower spring rates?

Save as much money as possible is not my intention. Wrong hobby for that. Throwing it away neither. But I'm willing to pay quality and manpower (blue printing).

Thanks!

EDIT: Sorry for the edits. The Forum did take off all returns firs.

[Pedigry]

Eaton truetrac seems to be the weapon of choice right now. Tough to find something that works as well as this. This is what I run in my restomod. It's smooth like butter. You don't feel it engage and disengage like a locker. I haven't owned a locker but I hear they can unsettle the car when they lock/unlock. The truetracs are very reliable, take a ton of power and the transition from full lock to open diff is unnoticable.