Engineers Were Busy
Certainly, said engineers already had enough to do in their efforts to squeeze the longer, wider, and heavier small-block V-8 into the tight engine bay of the H3, designed as it was for the narrower inline-five. Thus, according to H3 chief engineer Lee Visci, parts of the front-of-dash panel had to be moved rearward, and the frame had to be modified so that the engine mounting points could be accommodated and a new, heavier duty cooling system could be installed. The transmission was modified to accommodate a larger-diameter torque converter, and the front anti-roll bar was beefed up to handle the 100 pounds of additional weight.
Packaging of the exhaust system and the application of 2009 emissions controls made it impossible for Visci?s team to achieve the same horsepower and torque figures for their version of the 5.3 as, say, those in other GM applications, such as the
2007 Chevrolet Silverado, where it makes 315 hp, or even the ?07
Hummer H2, where it produces 325. ?We had to work very hard for that 300 figure,? Visci said. But she added that the team is very satisfied with the results of their efforts, which included a one-third increase in towing capacity to a now-credible 6000 pounds, as well as meeting the same safety standards (specifically for cabin intrusion in severe frontal collisions) as the inline-five model.