Well, the obvious answer would be to procure that exact pickup, or any split P pickup found in a MIM P bass of that era. Not the easiest thing to find, as I'm sure you've already found - not something you can just rock up to a shop and buy, is it?
It's actually making it harder, that you have a specific type of sound in your head. I've swapped pickups many times (probably too many times) but it has always been from the point of view of wanting something "different" but still "good" as my ears define it. My last P pickup swap was from some barely functional garbage in a G4M bass (one half of the pickup was microphonic for a start) to a Lace Aluma P, because I wanted to try something a bit different. In no way would I suggest such a pickup in your case, that's a completely different beast. My upcoming P pickup swap (again going into a super cheap bass) is going to be either an Entwistle PBXN (Neodymium) OR a Tonerider Duke because I fancy trying some high output P pickups and these two achieve this in different ways - the Entwistle by using stupidly powerful magnets (don't get the two halves stuck together - they're a nightmare to pull apart, in fact you have to slide them apart because the magnets are stronger than the glue holding them in place!) and the Tonerider by overwinding the coil.
Sorry for the shaggy dog story, I got sidetracked. TL:DR, I'm no help here whatsoever, and hopefully someone will be along shortly to tell you the name of a readily available aftermarket pickup which is a dead ringer for a MIM Fender job.