My 64 Deluxe Racer had the front wheel run over by the family car before I found it. I bought it crunched and it weighed 35 lbs stock with chain guard, fenders and no other accessories. After making it a bike to carry around spare Schwinn lightweight parts that I particularly like, it weighs 29lbs. One day soon I will have it painted and done up to perfection (my version)
Most all of the weight loss was in the front end. An Ashtebulah cast iron fork weighs three times what a Tange fork weighs. The wheels are old Alum Weinmann's that have a look similar to a Schwinn S-5.
Those are 700c's. Just a hair smaller than a 27, depending on the tires. There just aren't any choices for the Schwinn 26" tires. I've had plenty of those and have several sets on the wall. Sometimes I like to haul-ass and those slick bead tires scare me taking corners fast. The 700's have nearly unlimited tire styles and sizes, wire bead and clincher.
There probably aren't any Schwinn 26" alum rims for the earlier bikes, maybe the Sierra? But there are a lot of aftermarket choices for 26" rims that will work. Bringing my own hubs, then rims, spokes and set-up has been less than $200 the last couple times I've had it done.
It makes a BIG difference in rolling resistance when you can use high pressure tires