5.7 HEMI engine swap (MDS info)

Hey
I am helping a friend with an engine swap this Saturday. He has a 2011 Powerwagon with a 5.7 hemi (no cylinder deactivation) that has a bad cylinder. He picked up a rebuilt 5.7 hemi for a good deal but it was from a 1500 and we discovered it has the MDS cylinder deactivation. He learned it is just solenoid actuated but we don't know if it needs to be energized to keep it in 8 cylinder mode or, more likely to me as a failsafe, would be normally de-energized and energized to activate 4 cylinder mode. I'm sure we can figure it out just trying to plan out ahead any complications if anyone has any insight.
On the other hand, does anyone know what would be required to enable the cylinder deactivation functionallity on a 2500 that didn't come with it? Would the ecu need to be re-programmed? Any chance it could be accomplished with a tuner? (Not sure which tuner he has)

Any other issues with installing a 1500 5.7 into a 2500?

Thanks for any advice! It's been a while since I've played with engines and I'm getting excited

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Dunno if the 1500 program will play right in a 2500 PCM and CAN bus network (if you could get someone to do it). No tuner will enable it if it wasn't there to begin with.

Didn't think so, we're just going to leave it inoperable in the heads. Thanks for the reply. Wish us luck, starting tonight!

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Just take the solenoid plugs out of the 2500 engine and put them into the top of 1500 block, you can also swap the non-MDS lifters into the 1500 block but it's not absolutely required if you're not planning on a high lift cam that can collapse the lifters. And to answer your question, everything is disengaged until energized for the solenoids and the lifters are solid until the oil pressure unlocks them.

Ok we've run into a problem with his new headers. After cutting out the factory pipes, we realized they sent 1500 headers, not 2500 and they won't fit! Crap! Time to weld...

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She sounds pretty gnarly with just the exhaust manifolds!!

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