I bought replacement upper control arms for my 74 Road Runner. Tried unbolting the old control arm bar using a torch and breaker bar - snapped the bolt off.

How should I take off the control arm bar without breaking them - or was it just an age factor?

Where can I find replacement bars - junk yard only?

Really appreciate any insight offfered.  

You usually use 2 wrenches or/&  breaker w/3/4 socket and a wrench placed so that it's up against the frame/fender to hold it while you pull/push on the breaker bar.

So you need new upper control arm bolts?

Remember you just wanna heat the nuts and spray w-d to soak into the threads, as soon as you get that bolt/nut red hot it's junk.