I'm thinking this Raleigh of some sort (Grand Prix?) might be a good starting point:

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I picked it up recently along with a '73 Super Course frameset for $25 for both, so that puts me $12.50 in. Then, there's a rear wheel with an AW 3-speed hub in the storage closet that I trashed picked last fall. Hmm. Wonder how it'll ride with a 26 x 1 3/8" rear wheel and a 27" front?