IIRC, the Trek catalog showed the frame dimensions for all frame sizes in 1979 for the 710. Check the wheelbase against the brochure. If the price is right, could be worth it.
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72 Fuji Finest 76 Super Course, 72 Gitane Tours de France, 74 P-10 & 79 Tandem Paramounts, 75 Grand Record, 76 Grand Jubile, 84 Voyageur SP, 85 Miyata Sport 10 mixte 89 Cannondale ST400 and a queue