Dolan Pre Cursa / PreCursa / Track Champion

Follow this procedure:

1. Pick a crank that you like the look/price of.
   
2. Look up the bb that the manufacturer makes to go with this crank and the chainline for this pairing. The manufacturer's website is a good start followed by google. For example: On this page you'll see that the chainline for a Sugino 75 crank and a BB-SG75 bb is 42mm.
   
3. Google tell us that the length of the BB-SG75 is 109mm symmetrical . And it's an ISO taper.
   
4. Therefore if you wanted to get a chainline of 41mm for a Sugino 75 crank you would need a 107mm symmetrical ISO bb.
   
   

My basic point is that chainline is dependent on the pairing of crank and bb not just the crank. In general if you use a matching track crank and bb (Sugino 75 crank and 75 bb or Mich Pista crank and Miche Pista bb) you'll get a 42 or 42.5mm chainline. Knowing this you can select and alternative bb (of the same taper) to move that crank to a new chainline. To move a crank 1mm out you need a bb that is 2mm longer.

This assumes that the original manufacturer bb is symetrical....if it isn't you need to google the offset and work it out from there....

In your case the chainring either needs to be mounted on the inside or you ditch the crank and bb and buy any new track bb and crank pair as they will instantly give you a 42mm chainline which will be absolutely fine with a 41mm chainline at your cog.

Sorry this is a bit rambling. Hope you get the idea.