nice looking frame
If you are sure it’s a 27 wheel the best I have found are from single speed components. You could run a 700c too although as others have said you may need to check the brakes reach teh rim and if necessary swap for long drop models. Importantly you also need to check the rear spacing between drop outs – you may have something around 120-125mm. There are limited wheels to fit this so you’ll either have to shoe horn in a wider hub or cold set the frame wider as per sheldon brown’s website.
Although the frames are nice to ride components from this era can either be works of art or utter tosh. If its the former then i’d keep it original, if it’s the latter then i’d go single speed. if you have a new start kind of program near you they are inundated with bikes like this and have all the components coming out of their ears which they sell for buttons.
700c does give you a lot more tyre choice btw.
that blue would look cool with a polished stem,flat bars and single speed i think. From experience building up old frames with current components gets horribly expensive a bit too quick. If it’s good quality, older kit is suprisingly good once you get used to no indexing.