I can believe 12.4s for the 427 but a good LS6 should be right there too. The only dyno figures that I have seen showed an L72 making about 430 hp and an LS6 making around 460. The difference in weight and state of tune can make a big difference in how well these engines can perform. From the factory, with retarded timing and #68 primary jets, they sure didn't show their true potential. In about 200k miles about all that ours needed replacing was a water pump, fan clutch, and one valve spring. I guess they just weren't up to the rpm potential. Now, that's a good engine in my book. I was told back in the day that the COPO engines were honed out to the loose limit of the bore spec. Any truth to that. Ours revved as freely as any small block. Curious.
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Chevelleless after 46 years......but we did find a low mileage, six speed, silver 2005 Corvette. It will just have to do for now.
