Here is what I know and look for when I build my motors, for what its worth. Everyone has there own way of doing things, you just have to look into it your self and see what works best for you...
Everyone will tell you to run Co27's, they are awsome motors dont get me wrong. I have been able to get the best number out of them on the dyno, but when I run them they just dont have what I need. Cobalts are very easy to gear them.
Normally I look for this in my motors in this order;
I have found that my motors that are the fastest are the ones that have the most watts and pull the hardest. Watts = Power. People will tell you different to what works for them, and this is what works for me. Get the watts threw the brushes not running hard springs. For the Cobalts I normally run Red/Green combination. That really seems to work the best or Red/Red depending on certain goals.
I normally run Monster Stock's. They just seem to love my gearing methods, and I dont know why but I can make power out of them easier than C027's. When I build them I normally run this setup with a few hood changes and break in methods;
Cross Cut 99
Purple + / Red -
Normally I get around these readings on the dyno after 3 passes.
MP = 64-67 watts @ 11,000-11,900 rpm
MT = 930-990 torque
MRPM = 21,000 - 24,000 RPM
AMPS = 13-17 amps
Mid = 75-80
High = 85-91
^-general numbers using fantom dyno @ 5