99 Dakota...3.9 automatic , i allready swapped my 4.10 and auburn posi and put traction bars added my R/t wheels. Now its time to make the truck run I have a 5.9 with a RT10 Cam , ported heads, 1.5 roller rockers and air gap with demon 750 . I want this to go in this dakota...but i wanna know if i can rebuild the transmission in it to hold up to it or do i need to find a v8 tranny? Also do i need v8 front springs? If i can get the parts is it hard to to swap this to efi. any info on this swap would be greatly appreciated.. I wanna build a poor man r/t.

 

I would say yes. A V8 Tranny and Springs. I'm sure it need the support.

 

go with the 727. its amazing

 

As well, I have read lots of stories about people who want to do this but never read any about people who ever completed the project. A stronger tranny and heavier springs are a sure thing, what about the braking system on the R/T? You want to be able to stop that beast and I don't imagine the stock 3.9 brake system is as good.

For EFI you are going to need fuel rails, injecting system, your 3.9 computer I don't imagine will run the V8's ignigtion and timing system, as well as be able to control your asscesories when turned on. So a new computer and wiring harness.

Sounds like you have a great start to the project though.

 

I desided tonite that EFI is not gonna be very friendly...so i'm gonna use the exsiting wireharness to power my starter and alternator and use the gauges. The ignition and fuel will just sorta hang out tucked neatly somewhere. ...

What tranny does the v6 have and what tranny does the v8 have?

I'm not to worried bout braking..cuz just cuz i have more motor doesnt mean i'm gonna to drive it like a moron and not be able to stop.

 

Likely the 42RE, or so I believe the # is. If it is the 14 bolt pan then I am almost sure it is that tranny.

Aparently it will bolt to the 5.2 block, not sure about the 5.9 blocks? You could certainly try and run it with the stock tranny and hopefully not run into any problems until you can get a nice 727.

 

the transmission mated to the v6 is the 42re aka thea500 with O/D, the trans mated to the 5.9 v8 is the 46re... the 3.9 is based off of the 5.2 xcept without cylinder 7 and 8.. and the 5.9 is pretty much an over bored 5.2, the transmission from the v6 will bolt up the the 5.9, but the 5.9 will kill it in a matter of days because the 42re wont handle the torque output of the 5.9... and i bet the 3.9 brake system is exactly the same as the 5.9... just a general brake system if i am not mistaken, probabally bigger drums in the rear on the 5.9 trucks, doing this project will require the 46re, i would have it rebuilt with stronger internals, your going to need a drive shaft, update your rear axle from the 8 1/4 to the 9 1/4 to be on the safe side, your going to need your computers, wiring harnesses for the engine and trans, exhaust system, engine mounts, frame structure support, suspension, etc. not to turn you off from it but it's no weekend project. i would give it 3-4 weeks work time if done properly with all the right tools