When going for that 77 sound, there can be no underestimating the sound of the stock Travis Bean Pickups.
Unfortuantely I have never personally owned a Beaner, but god, one of my guitar students ( a Deadhead optomotrist) walked in to one of my lessons with a TB1000 and a TB500 and I spent the whole lesson playing his guitars.With the 1000 plugged in it was 76 JGB to a "T" and I am talking straight into the amp no affects, no nothing. I am used to hot pickups with Super 2's and I couldn't say for sure that the Beans were more powerful if you measured them output wise the probably aren't, but to my ear they just SANG. There was such raw power to them, but with a musicality that was stunning. The 500 definitely had the May 77 vibe going too. But I gotta tell you I am a big time mark for 75-77 LOM/JGB and I just could not put the 1000 down. I felt like someone was robbing me when the lesson was over and the guitar had to go back in the case. It was the first real bout of Gear envy that I have had in a long, long time. With 7 electrics and 4 acoustics and separate Weir and Garcia rigs, my wife almost threw me out of the house when I mentioned my longing for a Bean.
I have always wondered and have never been able to find any data on pickups that would give you that same Bean feel. I think it is moot anyway, because I think it is the custom pickups combined with their mounting right on an aluminum neck that creates the mojo, it is those two things together.
.......................................................have you heard the one about the yellow dog?