One thing to look is ground wire size. Do you have a good engine ground for that starter? If not see if you can measure the starter on how much it draws while cranking. A secondary way to do this is to measure battery voltage while cranking.

11.67@118 1.88 60' with only 7-8 lbs of boost. Turbocharged, megasquirted, 407 BB, 440 source heads, roller cam, 9:1 comp. http://s292.photobucket.com/albums/mm14/beansgracie