It will need more power, not sure on what tire size will fit stock. I run TrXus STS's in 31x11.50 and they rock in the sand. I run 25 psi on my CJ7 on the street...havent aired them down for sand yet...made it thru the washes just fine without doing so thus far.
Power...not gonna get too much with the stock setup. A 302 should fit tho!!