First let me update my situation:
78 or 79 Varsity campus green (66cm frame). I got it completely stock, replaced stock wheels with new 27" alloys. It rides like a new bike.

My question relates to the avg. top speed of these old 10 spd tanks. In the last gear 53-14, the BB will vibrate. I can spin and mash it vibration-free in the lower gears. Also, recently the BB has been making noise, like coins jingling in my pocket with every stroke. If I went through all the hassle of rebuilding/replacing the BB, would it net me any top speed over my current 22mph? Or am I just weak? I'm just itching to get a decent road bike under $700, but I'd hate to find out my old tank could have kept up with it after some maintenance.

Thanks

Time to take the BB apart, some BMX parts should fit, description suggests a cracked ball bearing or worse, I did 38 years ago rebuild a Schwinn BB using loose ball bearings that provided almost 30% more bearings to carry the load. Tricky assembly though. If you wish to go fast, use the kinetic energy at your disposal going downhill.

If you like the Varsity look, find a Super Sport.

be seeing you

That failing BB will be stealing a little bit of efficiency, and servicing or replacing it might help in regards to effort-expended-per-pedal-stroke.

Sheer speed is mostly the product of the "motor", in bicycling. Weight means very little as far as top speed (on level roads) goes; it just might take a little longer to get there. More important factors are Aerodynamic resistance, frictional losses due to rolling resistance, and gear selections that allow you to pedal at your most efficient cadence.

It takes a very strong rider to turn over a 53 X 11 at any kind of cadence....

I replaced the one piece crank on my Varsity with a modern three piece. Made a big difference.

It's easy to do, all you need is a BB adapter (about $20), a modern 3 piece crank (I used a Shimano Sora), and a cartridge BB ( I used a 110mm length but it depends on what crankset you use).

The best upgrades one can make to a Varsity or Continental are:
1) new brake cables and housings;
2) KoolStop brake pads;
3) aluminum rims;
4) aluminum cranks;
5) "ultra-6" freewheel

1) Done -- Shifter cables and housing also.
2) Done
3) Done
4) Done
5) Used a new 5 speed Shimano, an ultra-6 freewheel requires a narrower chain. I found a NOS Sedis "Sport Chain" on eBay, still in the package. The old Sedis chains are impossible to break, in 30 years I've never broken one.

I also scrapped the old Varsity steel handlebars and forged steel stem -- damn stem must have weighed 5 pounds by itself. I used the alloy stem and handlebars I snatched off a Continental with a girls frame -- the bike was hardly used, all the parts were like new. The alloy handlebars and stems used on the Continentals were actually very light and high quality, the were made by "GB" in the UK.

I'll post pics of my Varsity when I get some time.