Features:

• Premium fitment with optimized ground clearance; the only 1970-74 and 1975-81 specific header designs in the marketplace
• Laser cut 3/8" flanges with flat-finished TIG welded port sealing
• 1-3/4" primaries
• Compatible with QuickTime bellhousings, mechanical clutch linkage (requires custom Z-bar/pivot ball assembly), stock A/C evaporator case on firewall, straight boot spark plug wires and Holley LS swap oil pan and accessory drive brackets
• Compatible only with stock height subframe/body mounts; installation with half-height mounts will require modification to vehicle floor panels

Application Notes:

• Stock LS1/LS6/LS2 or 5.3L-6.0L Vortec truck engine swaps requiring maximum ground clearance
• These headers were not designed for bolt-in compatibility with a 4L80 transmission. The ears on the side of the transmission would have to be trimmed for clearance to permit the installation of these headers

Required Brackets:

• 520-12613 1975-81 LS Swap Engine Mount Brackets
• 520-12614 1970-81 LS Swap 4L60, 4L65, 4L70 & 4L75 automatic transmission crossmember
• 520-12616 1970-81 LS Swap T56/T56 Magnum manual transmission crossmember
• Sold Seperately