How fresh of a build is it? Someone suggested running the compression numbers and a leakdown test. Good idea. On a street engine it takes a while fro the rings to seat. Second don't start changing a bunch of stuff the carb and intake are OK. Beg, borrow or steal a C02 meter and run the test yourself, I'm douptful the F/A mixture was dead on. They use an exhaust sniffer they poke up the exhaust pipe and they're not accurate. Do the basic tune up stuff before you fall for change this and change that. You're not that far off from a typical street 440. By the way a 68 Hemi RR would run high 13's and a Cuda mid 13's in stock form. If you wanted the fastest you bought a Cuda 440 6pack in stock form, it was thge fastest.