They "should" be 7/16" banjo bolts till around 1978,after then they may be 10MM...if your going to buy calipers I would wait till then,and just match the bolts up to them,sometimes a later caliper with metric bolts gets used as the core,and you end up having to get the hoses that match too ,I have run into this more than a few times when I sold parts at stores and it may have been they were just boxed wrong,but maybe not...usually its best to replace all the parts at the same time,because when one is old enough to need replacing,all of them are probably due...it also aviods troubles with bleeding,one caliper sticking after you replaced just one,pulling,etc,when an old hose or caliper acts up...
The other end of the hoses take 3/16" line fittings with a 3/8x24 thread,inverted flare...
