When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So I plan on building a new motor for my truck using 3 bar GT40 heads that I’ve had laying in the garage for a couple years (new seals but they might need to be replaced due to sitting?) and I have a couple questions.
First, I plan on replacing the valve springs to handle higher lift and I plan on using a set (https://www.alexsparts.com/sb-ford-g...ft-vsk7h48-13/) from Alex’s Parts that handle up to .550 lift without mods, but I’m not sure about the valve stem length differences it mentions.
Second, and I know it’s pretty beat to death, but how well would GT40 heads, a Comp Cams 35-349-8 and maybe shorty headers pair up with a Speed Density 302 in a ‘93 Bronco?
The exhaust valves on these and many other Ford heads have shorter stems than the intake valves and to account for this the factory exhaust springs are shorter so the same retainers can be used on all. These aftermarket springs are all the same height so to get them to work correctly(have the same closed seat pressure and spring rate) the exhaust retainers have to be different.. they will have a deeper dish.
That cam, heads, and exhaust will be too much for both the truck EFI control system and it's fuel delivery components, all together that combo will make well over 300hp which is more than the stock injectors can supply.
So after some research about casting numbers, I decided to look at the bottom of the heads and the casting is F3ZE-AA which combined with 1/2” head bolt holes indicates these they came off of a Lightening, correct?
Also, I’m attaching pictures of the rocker arm mounts and they look as though they’re already set up for screw-in stud mounts. Is this correct?
The valve stems are all the same length, the position of the lock grooves is different. If the stems were different lengths, the pushrods would have to be as well. The only SBF heads with shorter valve stems are in the E6SE heads.
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Slideshow: The VelociRaptor Expedition gains a lift, upgraded suspension, Brembo brakes, and trail-ready equipment while retaining the stock 440-horsepower EcoBoost V6.
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
