Brendan;

Most of the wearout internals (I'm thinking of the fiber washers) of the distributor can probably be replaced with industrial standard parts... As far as replacing the springs and/or centrifugal weights, inspect them and worry about replacing only if they really need it...and if the dist was halfway lubricated, then they'll likely not need it...see also: http://www.sw-em.com/Volvo%20Ignition%20from%20Scratch.htm#Detailed%20CA%20Servicing if you do need internal specific parts I doubt they are stocked stateside...possibly at Bosch oversees...

If your'e installing an electronic IGN upgrade, you either install a power OR'ing cable as other poster suggests (see: http://www.sw-em.com/Volvo%20Ignition%20from%20Scratch.htm#Vintage%20Volvo%20Ignition%20system%20and%20the%20Armored%20Cable ) or, if you've previously, or are going to, do the smart thing and install a Start Switch Upgrade, that's not even necessary, but there is absolutely ZERO reason to insult the armored cable...ever(!)...that is our anti-theft measure...and I don't recommend compromising it!

Cheers