Help identify Detroit locker

[408sbfmustang]

Hello
I have a One of those NASCAR 9" 3rd member with a Detroit locker in it. I'm trying to figure out what spring is inside of it. Looks like an natural color.

Scribed on the locker case is.

170
N178A
71773
28A03

[Mach1_Ron]

Might check out this page and see if it helps....
http://www.kevinstang.com/Ninecase.htm

[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.