Speed Engineering 1979-2004 Mustang Gen V LT Swap Headers & Optional AJE K-Member
Speed Engineering 25-1166 1 7/8-inch longtube headers for Gen V GM LT engine swaps into 1979-1993 Fox Body and 1994-2004 Ford Mustangs. Mandrel-bent 304 stainless construction with 3-inch collectors, merge spikes, CNC-machined flanges and included graphite gaskets.
Choose the headers alone or the manufacturer-matched package with the 1979-2004 AJE K-member, LT engine mounts, spring perches and manual/power steering-shaft kit. Header fitment is validated around the AJE components; other combinations are unconfirmed.
Every header configuration can be upgraded with SMG LT MLS gaskets and/or SMG 9070C Ceramic Plug Wires. Their ceramic boots resist header heat and melting, and they are the only wires used on SMG in-house header builds.
Processing & Shipping Overview
Processing occurs before shipping.
Most in-stock items typically process within 2–3 business days before shipment or pickup. Expedited shipping options affect transit time after an order ships and do not speed up processing.
Made-to-order, special-order, vendor drop-ship, and freight items require additional processing time before shipping. Any extended lead times will be noted on the product page when applicable.
For the most up-to-date order status or lead time questions, please contact sales@smgspeed.com or use live chat during business hours.