14. 5.3L Stock vs. Modified the results were nearly identical on the slightly larger 5.3L. In stock trim, the 5.3L produced 344 hp at 5,100 rpm and 379 lb-ft of torque at 4,300 rpm. After adding the same TEA heads, Crane 224/232 cam and Fast LSXRT intake, the peak power numbers jumped to 484 hp at 6,800 rpm and 424 lb-ft at 5,700 rpm. Like the 4.8L, the 5.3L lost no power even down at 3,000 rpm, but the gains exceeded 150 hp past 6,000 rpm.