Cobra Gt-40 NOT P...casting # #F1ZE AA

Old post I know... but wanted to add...

FoxChasis is correct... The GT40 "Cobra/SVT" head was developed for the upcoming factory SVT Cobra Mustang and was also used on the SVT Lightning truck. The original Motorsport casting was the F1ZE-AA and received Cobra tweaks by Ford Motorsports Division such as milling for higher compression - some bowl blending, etc. It is true that Ford used the untouched (as-cast) F1ZE-AA for its Marine head for a good long while thereafter. They also used that as-cast "non-Cobra/SVT" Marine head in the '96-'97 Explorer.

Ford wanted to have the entire Cobra engine package (engine/head/intake/smog provisions) stamped as "approved" by the government instead of having each piece passed individually - so they gave the pre-SVT Cobra package to SAAC who further "tweaked" (to 295 dyno-hp) the package to produce the Shelby AAC Mustang MK1/MK2/Snakes in '92/'93/'94. So, the only true "Cobra/SVT GT40" heads stamped F1ZE-AA ever used were on the '92 Shelby AAC MK1 and possibly the '93 MK2. When Ford got the smog-legal A-OK from the gvmt - they then cast the factory SVT Cobra heads for the '93 SVT Cobra using F3ZE-AA and '94 SVT Cobra F4ZE-AA - these were also available from Ford Motorsports as part number M-6049-L302. I can only assume that Ford made tweaks to the head design as they re-cast each head from F1/F3/F4 but they kept using the original as-cast F1ZE-AA casting in their Marine applications.

So, people use the term "Cobra heads" very very loosely - esp on Ebay - when selling or describing their GT40 heads. The only true F1ZE-AA "Cobra/SVT" head are on the very limited production Shelby AAC cars... if you have F1ZE-AA stamped heads on any other Mustang - rest assured they came off a '96-'97 Explorer and are just Marine heads. Better term when using the F3ZE-AA/F4ZE-AA are SVT (Specialty Vehicle Team) GT40 Ford Motorsports heads since they were used on both SVT Cobra Mustang and SVT Lightning trucks.