The factory battery is probably in the neighborhood of 580CCA. The battery you sized will probably be available in 700-800 CCA.
That's what I came up with on my L4240. I am pretty sure was was recommended was a group 24. However, a group 34 was 1" SHORTER and was 800 CCA instead of the group 24 700 CCA, and the group 34 was $10 less cost at Walmart.