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Q: Do I have to change the engine mounts and bellhousing when switching to the 3.9l?

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I want to switch my 3.5 l g6 to the 3.9 and was just curious what all I would have to convert to do it?

My car has 120000 miles.
My car has an automatic transmission.

The engine should bolt up to the transmission, but the 4t45e has a lower torque rating than a 4t65e so pushing more power through it might cause problems. There may also be a few subtle issues with mounting the new engine into the car. It would be best to drop the subframe with a good engine, trans and electronics from the donor vehicle and swap it all into the car. You’ll have to do a lot of research on this one to get it working right.

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