Lethal Performance is a leading retailer of Lund Racing tuning. Fortunately Lund Racing’s Ken Bjonnes also works out of the Power by the Hour facility, so in-house custom tuning is readily available. These days, changing hardware on a modern Mustang means changing the calibration in the PCM. Fortunately, Ken is well versed in these combinations, and he worked with Jon to craft a custom tune for this 4.0-boosted, MPR Racing-built Trinity 5.8. With the new supercharger and custom tune in place, it was time to strap Lethal’s ’13 GT500 down to Power by the Hour’s Dynojet chassis dyno to reveal the results from the 4.0-liter supercharger upgrade. There’s no doubt the ’13 Shelby GT500 is a stout performer right off the dealer lot. It also responds well to the usual bolt-ons as we found out in our first installment on this car (“Let It Eat,” Nov. ’12, p. 74). However, when the engine is fortified and big boost is applied, this combination turns into a monster.