Originally Posted by
fordfasterr
for an 83, you'll need to either bend the seat stays to fit a modern width rim, OR have a custom wheel dished / spaced to fit into that frame.
This is bassackwards, to spread a 120 or 126 mm rear end to fit a modern 130 mm freehub that you have to buy and then lock out the freewheeling capability of said hub.
You can buy fixed gear wheel sets with flip-flop 120 mm rear hubs that will slip right in with little or no cold-setting. Flip-flops are threaded for fixed gear on one side, single-speed freewheel on the other. Your local shop can order them for you, or you can buy online through any of dozens of online stores. I recommend NYCBikes.com and BikeIsland.com. Decent wheels can be had for $110-$200 plus shipping.
Chainline should not be a problem if you use a single-speed crank with short (108-112mm) bottom bracket spindle. BikeIsland has a nifty FSA crank with chainring for $40. A BB would be another $25-30.
Converting a fixie is about solving problems in the most direct way you can.