Been a long time FE fan....... I recalled hearing a "little" trick from a Shelby GT500 "NHRA stock" racer. 428 FE Gent's slipped through NHRA via good-ol Carrol Shelby stated to NHRA (that the 68 GT500 came with an Alum 4V dual plane PI Intake) -- thus was approved.The existence of 428CJ/SCJ with factory alum intakes are hens teeth..... The 428 churning to a stated 7,300rpm shift // 8,100 traps scrambles my brain... I recall a NHRA Super Stock running a sleeved down 427 block to add strength to bottom-end. Running a flat-tappet with a factory dual plane is so utterly contradictive to Jay Brown's book The Great FE Intake Comparo" it's mind bending