i used to ride a touring Cannondale and swap between 7spd freewheel 27in wheels and 8spd cassette 700C wheels. the only adjustments were to the canti-brake angle and moving my 8spd bar end shifters in and out of friction mode. or were they 7spd index shifters? anyway, you get the idea.
Thanks for the info on a 27" 7sp freewheel➜700c 8sp cassette swap--I'll give it a shot....
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just tried it & just as I had read--the brakes have to be lowered ~4mm to go from 27" wheels ➜ 700c.