Hi Whelan,
The quad piston calipers from the 140 series car will not directly fit the 1967 model 122. The 120 series that you have will have originally been equipped with the Girling 3 piston front caliper setup. AFAIK, the only other cars that were fitted with calipers that were based on these, were fitted to some Jaguars and some other English 'sport type' cars of that era. I should have a set of calipers that will suit your car if you have been unable to locate any (lets say, $50 a pair plus whatever the postage ends up being). They will need to be rebuilt, but it is actually relatively straight forward. I recommend unbolting the two halves, cleaning everything to within an inch of its life, and fitting all new seals etc, (including the little one that goes between the two halves of the caliper).
As for the brake lines, the original Amazon ones are steel, and rust is a problem. Better to use the copper-nickel alloy type as fitted to later Volvo's.
Feel free to call me on 0428 213 983 if you need the calipers.
Pleased to hear that another 120 will be back on the road.
The 144 parts car will be useful for the engine, gearbox (manual that is, don't waste time sticking an auto in it unless you REALLY have too...), and some electrical bits possibly..
Good luck.
Cheers,
Richard.