Originally Posted by
agmetal
I just took a closer look...even if it's not all original, the derailleur and shifters do match.
Anyway, I'm going out soon to pick up a new shifter cable, so I'll report back once I've got that installed. I'm gonna start with Sheldon's technique and see what happens.
That set up will not index properly. You could probably tune it so that 4 cogs will work OK. Just use friction mode with that 105 shifter.