Thanks. I'll take a look at the chainring fix since you are the second person to recommend it. Now I need to figure out the BCD on the existing crank.

The bottom bracket on the bike seems fine. I know it's old, but when I got this bike last May everything was original spec right down to the tires which were still serviceable. I have replaced them, but overall condition of this bike is very good at worst. I really just want to get a little more top end speed.