Edited on 2015-04-02 14:49:18
I used this place for my 67 OTS restoration: www.turnswitch.com

I tried a couple of pairs of modern speakers but never found any that would fit properly as most of the magnets are too deep. The speakers from the outfit above fit perfectly and sound as good as you can expect for the location. Quite honestly, I now just place my Bose Soundlink Mini on the dash and get much better sound for those rare times that I'm not enjoying the sweet exhaust note!