NA 4.6L PI vs. TFS street Burner Intake. Prior to installation of the Kenne Bell Mammoth kit on the 4.6L, we took this opportunity to run a quick intake test. The modified 4.6L was run first with the stock PI intake and Accufab throttle body and then again with the TFS Street Burner intake. The TFS intake offered substantially more peak power, upping the peak numbers from 348 hp and 349 lb-ft to 371 hp and 331 lb-ft. The long-runner PI induction system offered more power up to 5,300 rpm, but the TFS intake offered as much as 45 hp at 6,500 rpm.