If you have a good battery and the right sized cable, there's no need for 2 batteries. Unless you race w/ no alternator and don't take a battery charger to the track w/ you.
My car just has one battery and a 1/0 cable. Has always worked great w/ the 11:1 572" hemi and the previous 14.5:1 446" wedge.
FWIW...the Camaro I drive has a 14:1 436" sbc and has no alternator, but does have two batteries. It still cranks fine on just one battery, but lasts longer b/t charges when racing w/ two.