Factory KH 4-Piston Calipers

I am looking for good (useable/rebuildable) calipers as came from factory with (small bolt pattern) front disc option. My original units were NOT rebuildable so had to be scrapped. I plan to upgrade ('70 Swinger) to the '74 Duster setup, yes, with larger bolt circle, and then convert my Signet's 9-inch drums to the (4-piston) discs - initially as manual. Just getting some feelers out there. I hesitate to purchase new/rebuilt from usual businesses as the cost of these items and the core charge will be very high. thanks.
p.s. I already purchased the rebuild parts - before I knew my calipers were hooped.
NOTE: I should also add that I will give first consideration to CDN sources - again due to punishing $ exchange rates, shipping and taxes. thanks.