The battery specified I believe is 550 CCA. However, a slight modification to the battery tray can allow for a 900 CCA battery. The battery itself is approx 1/4" wider (give or take 1/8") For you fans of the Metric System ther are conversion tables in the front of the Eagle Service Manual.
Anyway, Remove the tray, & with a hacksaw or cutting tool, make a cut on both ends of the tray facing the engine bay. (This is on the longer side of the tray, flatten out the lip & reinstall the tray. You will now have room for the battery. NOTE: The area between the battery & AC line will be very close. I have put a wooden scrap of lath under the leading eduge of the battery to keep it from touching the AC line. It has been in my car for over 10 years & 2 batteries. The weight of the battery will hold it down, but a strap could be fashioned if you are creative.