Help identify Detroit locker

[1BADBET]

I think the only way to know what springs are in it is to take them out and use a spring checker. They are most likely way too stiff for any street driving. When I bough my nascar 3rd member off eBay (5.14 gear) I just double checked lash and the wear pattern and called ron sutton to get new lightweight springs. I think he's the only one around selling them as far as I know and they are fairly inexpensive. Just give him a call and tell him what your using it for and he will get you set up with the right stuff.