Please tell me you're not replacing the pickup in a 28 year old bass.

If the pickup is original, then do yourself a favor and get another bass to mess around with changing pickups.
If the bass is already modified, I recommend you searching this forum for the word "Reverend". Reverend is selling off their old stock parts pickups since they quit making basses. The pickups are a mere $12 and are IMO as good sounding as anything else out there at any price.