Try this mail order site for electrical upgrades and aged parts etc. I have dealt with them a few times and had great service.
http://www.rsguitarworks.net/catalog/index.php
My recently acquired '85 LS80 had lost its circuit board and had some crappy small pots installed so I fitted one of RS's upgrade kits which included 4 CTS pots and new caps.
My guitar needed the historic spec kit which uses shorter shafted pots so measure before you order. I am very pleased with the results and this was only the standard kit they also do a more expensive premium kit with more exotic caps made exclusively for RS Guitarworks.
I have also changed the switch (which was a pretty new budget replacement type) and jack socket for Switchcraft items so that everything in the chain is top quality.
I have also got some sprague orange drops which I will try sometime to see if theres any difference in tone or pot operation. If there is I'll post to let you know!
By the way I fitted a fitted a Seymour Duncan alnico 2 pro neck model pickup in the bridge position as it was the only black open coil pickup I had handy and it sounds great so dont assume that you have to use the necks or bridges in the "correct" location.
The SD measures 7.6K and the Tokai neck pup measures 7.3K so they balance nicely.
The original bridge pup is faulty it gives no reading on the meter and a nasty bright thin tone, the wire had been cut and then joined long ago but the joints appeared sound so can anyone suggest what is wrong with it? A dodgy winding coiltapping itself perhaps?
Hope all this of some interest/use to someone!
Regards
Simon