As with most decisions in life, there are pros and cons to swapping out the 5.7 HEMI intake manifold for one designed to work on the 6.4 HEMI. So before we dig into any expected gains, let's discuss the elephant in the room: how much is it going to cost? We explored three options for 6.4 HEMI intake manifold swap kit pricing, Moe's Performance, Modern Muscle Xtreme, and Street Driven Performance. Prices start at about $1,600 from Moe's Performance and Modern Muscle Xtreme (MMX) and just north of $2,000 from Street Driven Performance for the complete, ported 6.4 HEMI intake manifold, SRV controller, and wire harness extension.
Moe's Performance advertises gains of 29 horsepower and 16 lb-ft of torque at the wheels from the intake manifold swap. However, in addition to the intake swap, Moe's results came from a 5.7 HEMI equipped with a more aggressive cam and long-tube headers.
Tallguyinahemi questioned whether the swap was worthwhile on his YouTube channel. In the video, he estimates a 5 to 15 horsepower gain from the 6.4 HEMI intake swap, but notes the most significant gains are for low-end torque. YouTuber Neverenuff achieved a seven-horsepower gain from a 5.7 HEMI-powered 2015 Dodge Charger using an 89 octane tune when swapping to the 6.4 HEMI but saw a 20 lb-ft of torque boost.