For what it's worth, it's very possible mix and match parts with non-indexed downtube shifters. I converted my Nishiki Prestige from the original Sugino VP 165mm double crankset 52T/ 42T with 6 gear cassette 13T - 26T, to a triple crankset and new wheels with a mtb cassette/rear derailleur. It was surprisingly cheap and easy.

Original drivetrain, with which I couldn't make the Santa Anita/Chantry Pavement climb.


This is a summary of my mods:

1) 48/38/28 triple 170mm square crankset up front (took the 52 from the double crankset to replace the 48, $16 used).
2) Re-spaced the rear triangle to accommodate my new Maddux wheels (135mm, $60 new wheelset). Tires kept slipping off original wheels anyways.
3) 12-32T 8-speed cassette (SRAM PG-850, $20)
5) Old MTB 8 speed XTR rear derailleur (lying around in the garage, free!)
6) 68 x 127mm BB. Eyeballed and measured up the spacing required to accommodate the triple (Shimano UN-54, $19). This part cannot be underestimated. The original 116mm BB
with a triple would not work. The granny front ring would literally mash into the rear
chain stay and not allow the cranks to rotate.
7) SRAM PC-870 chain (8 speed, $15)

$130 with almost all new drivetrain parts, along with a new bottom bracket and a new wheelset. Shifting is like butter with the non-indexed shifters. The bike still weighed under 24 pounds and I'm able to make the Chantry Pavement climb 50% faster than guys with mountain bikes.

Here it is now (more or less):