Motorcycle Repair: Best battery for the situation?, odyssey batteries, plug holes

Question
I have a 1982 FXWG I put on a horseshoe oil tank a few years back and have a 310V battery in it now.  I had the motor punched out to 93ci this winter and now the starter will not turn over the motor.  I have a new Spyke starter on it and was told by the person that re-built the motor  ( A very respected former AHDRA top fuel NATIONAL CHAMPION.)  That I needed to try a battery with more CCA.  I have found a Big Boar battery that has 350 CCA but am not sure that is enough.  Can you recomend a battery that will fit in the space I have ( 7"Lx4"Wx6 1/16"T) approx.  I have been told that ODYSSEY batteries have 535 CCA for some reason found that hard to believe.  A second opinion would be great.  Thanks,
Mike Morris  

Answer
I have a 96 CI motor that turns over with a stock battery. You never said what the compression is, but it must be high. Instead of goign with a bigger battery, which is expensive and will need replaced intime, I would go with compression releases.Spyke has a set that goes into the spark plug holes so no drilling
Good luck and happy riding
Mike