I’m a newbie to the gen III swaps. I have a 96 Dakota 2wd that I’m putting an 08 5.7 in. The truck was a 3.9/42re, it has the o/d button on the dash. Can I use the 42re if I have it built to handle the extra hp/tq of the hemi? I’m just not sure how the electronics work to control the trans. I also have an a500 trans. That I could use. Should I find a 46re? Or? Thanks!

I gathered the parts to install a 6.4 crate Hemi into a 68 Coronet wagon, so not a light car. I am going with the Holley Engine Mgmnt System. For the trans, although Holley has the ability to control the 46RE (extra harness purchase) I went with the A500 for the better-for-me gear set (2.74, 1.54, 1.00 and .69) I am replacing a A904 so the kickdown linkage can be re-used. I had the A500 built up to handle the extra HP/TQ. I purchased a Billet Lockup Converter from Edge Racing Converters. My swap wont happen for a while but I have all the parts I can think of without the engine/trans in the car. I have to admit, Holley seems to have nearly everything necessary to handle the swaps.

Keep in mind for the 46RE, 46RH, 42RE, 518 etc, those transmission need throttle linkage to control the 1-2 and 2-3 shift. The 3-4 is controlled by the computer in the RE trans. 3-4 is done with pressure switches in the older RH transmissions via the PATC kit. You'll either need a cable driven throttle body or the Bouchillon Throttle pressure cable system. Or at least you'll need that to keep it a true automatic.

You can go to Cope transmission and get a manual valve body which simplifies things, but kind of defeats the point of an automatic trans. Cope can also steer you in the right direction to build the 42RE to handle additional power. 46RE seem to be fairly easily found at most pick and pull yards. The 46RH is a little more difficult as your talking 95 and earlier. If the Holley unit will control the RE, that seems to be the right choice.