Hard to say. What did the throttle cable that broke come from? I'm using the one on my 302 that came from my 351w that was originally in the car when i bought it. I would guess that they interchange. Try finding a 73 with a 302 in it. Or order one fromcheckers or auto zone. If it comes in and it's different, just tell them no thanks.
i would think just about any stock v8 cable would do it. arent there even some v8 swap guys out there still running the 6 cyl cable?
Stang cables work too. Just have to watch out for the 2 different types. There is a 2 hole and a 1 hole. I forgot how they pan out in years. You can use the I6 cable too and usually find it easier/cheaper than a genuine Mav v8 cable.
i bought a universal throttle cable kit from checker/autozone when i put in my 302, since the throttle cable wouldnt reach from where it was to the new 302. it cost me about $15 and came with everything to connect the pedal to the carb