2007-2012 5.4 L Shelby GT500s should expect 680-800 rear wheel horsepower (750-900 crank HP) with 2.8”-2.5” upper pulley sizes on the stock engine. Overdrive lower pulley NOT required.
2013-2014 5.8 L Shelby GT500s with the factory 2.3 L TVS will see huge improvements with the VMP 2.65 L Gen3R TVS due to the higher twist and resultant efficiency increase with the new 2.65 L rotorpack. You can expect 750-800+ rear wheel horsepower with a 2.6”-2.5” upper pulley on the stock engine.
800 rwhp is the recommended safe limit on the stock engine and the VMP Gen3R can easily achieve that with supporting modifications and good fuel (E85 or 93+boostane).
Built engines with forged pistons/rods, aftermarket camshafts, and cylinder head porting can see 1000+ rwhp depending on compression ratio and fuel used. 10% or 15% ATI overdrive pulley recommended and available from VMP.
Check out this video link where Lund Racing made 1250RWHP SAE
Our kit includes all necessary parts and hardware to upgrade the head unit.
Gen3 and GenR require a minor modification to the cooling tower with the provided milling tool, click here for the instructional video.
Pulley Size
Boost 5.4L
Boost 5.8L
Fuel Octane
3.0”
16psi
14psi
91+
2.8”
18psi
2.7”
19psi
17psi
93+
2.6”
20psi
93+ Boostane or E85
2.5”
21psi
2.4”
22psi
For stock engines on 93 octane we recommend a 2.8” on the 5.8 L and a 2.8” on the 5.4 L
For stock engines on 91 octane we recommend a 2.9” on the 5.8 L and a 3.0” on the 5.4 L
Fits 5.4L and 5.8L engine
