Swap from charger 5.7 to 6.4

[Weezycuz21]

Reviving an old thread because I just did this swap. I installed a 2020 6.4L from a scat pack Challenger into a 2018 300C 5.7L. It's still using the stock 5.7L 8HP70 but with a 1320 torque converter installed. 3.09 differential installed. PCM is a new unlocked HPT unit. I flashed in a complete calibration from a 2019 1320 Challenger and the car runs and drives fine under light throttle, but under WOT the PCM never gives me full throttle except for a few blips after shifts, never makes full power. Appears to be torque managing itself down. When this happens, the Throttle Input PID says: Transmission, and when I momentarily get actual WOT is says; Pedal. I take this to mean the transmission is torque limiting it. No faults from the transmission or engine that would limit power.

My question is for any of you who have done this swap, did you have any transmission issues like this afterwards and if so how did you solve them?

[Weezycuz21]

Did you get it figured out?

[royallee]

Hey, my car is a 2014 charger rt, i swapped my engine from a 5.7 to a 6.4 im trying to figure out what's the easiest way for me to convert my 5.7 tune to a stock 6.4 tune. do i have to copy parameters one by one, or i can just use a stock 6.4 tune from the repository.

i need help, its a complete stock 6.4 engine, i also got the intake runners to work with an MSD switch so they open up at the same RPM as a stock 6.4.

HELP

[royallee]

Did u use your 5.7 wire harness with the 6.4 pcm and bcm or just the 6.4 pcm with 5.7 bcm