SUCCESS!! The bike that I got from the thrift store for $2 had a chainwheel
that fit my Nishiki perfectly. It is a 40 and I cleaned it up and put it on
the Nishiki and rode. Now my crankset is a 54-40. I can't believe I found
one that fit. Next I need to find some shifters. I can't stand the
shifters up on the stem. I will move them to the down tube. I'm sure I can
find a cheap set somewhere.
Wish me luck!