4.8L vs 5.3L (Modified)
The difference in the respective power curves continued after the modifications. The larger 5.3 offered more power through most of the curve, but the difference diminished with engine speed. In modified trim, the 5.3 produced 484 hp and
424 lb-ft of torque, while the smaller 4.8L managed 476 hp and 392 lb-ft of torque. The smaller 4.8 nearly equaled the larger 5.3 in peak power, but both peak power and peak torque occurred 200 rpm higher in the rev range. Given the
shape of the curves, we suspect the 4.8L had even more power to offer had the heads been set up with even more valve spring pressure to allow for extended rpm up to 7,500 rpm.