Donald;

Matching up a component is always a good practice, but in this case, while you have it removed from brake system hydraulics, and bring it to that parts store, the system will be leaking fluid, necessitating a major bleeding...not such good advice IMO. ...and if that parts store can supply you with a replacement, you're only back to the unreliable, late-acting (insert additional rude descriptive here!) setup which will function reliably for who knows how long (or short). See: http://www.sw-em.com/hydraulic%20brake%20light%20switches%20notes.htm

If you insist on keeping the pressure sensing brake-light switch setup, buy an OE replacement from ipd and install as other poster suggests...if you're quick about it, and don't dilly-dally between removing old switch and installing replacement switch, you might not even notice the pedal get any softer.

My advice is to convert over to the reliable and early acting pedal position sensing setup as Volvo also did in 67-68...BTW, you leave the OE switch in place and install the upgrade switch discretely in the footwell, so the appearance is quite original...

Full Disclosure: I offer these...but I sure as hell ain't payin' off the house with profits from them!...other poster has given link (thanks for the reference!)

Cheers