Fixed Gear Project
 

Hey guys! I recently bought a 1979 Schwinn Varsity equipped with a Front Freewheel (FF) System. I was wondering if I can replace the crank so it's not freewheel? Lastly, what should I know about the bike about which parts to keep and which parts to sell? Thank you guys in advance!

Well, that's not exactly a fixed set of gears in the back. It'll freewheel if you put enough torque on it. Little safety feature Schwinn put in there for you.
If it's got the Positron shifters with the unique cables, and they're in decent condition, folks will want those.
What size are the rear cogs? My neighbr might want those if they are bigger than his.

If I'm not mistaken, I think all of front-freewheeling (FF) systems came with 14-28 in the rear.

Bummer. He really likes his FFS bike but he sees the triple crank hillclimbers that I build and asks me if I could make him an FFS triple. Well, with a little cutting and welding and machining, sure.