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Discussion Starter #1 (Edited)
HI, I'm new to this forum. I looking to do Cummins 4BTA a swap on a 74-79 Jeep J10/J20 4X4. I would like to know what is involved as far as parts. (i.e: transmission, Transfer Case, drive-shafts, differentials, bell-housing and of course the engine.) A rough Idea on cost would also be good. (i.e: $10,000-$20,000.). I also would like to know what kind of performance the 4BTA gets compared to the AMC 360 V8. (Looking for MPG). Also the Power/Torque performance of the 4BTA. ( I'm looking real-world numbers not just specs.) I would also like to know How loud the Cummins 4BTA is, and how I can quiet it. (Because of neighbors.)

I realize these questions have been asked a million times before but I want to get all of MY questions asked before I even think about a project like this.

Thanks

Brandon

PS. Would it be possible Swap Cummins 6BT instead of the Cummins 4BTA? Just curious.
 

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If you visit the performance section of this site, you'll see that there is a sticky with people reporting their Dyno numbers and what mods they did to get those HP/Torque numbers.

Look around at the build up threads to get an idea of what transmissions/transfer cases/axles people are using. Popular choices in manual transmissions are the ZF ford, NV4500/NV5600, or the SM465. Popular choices in automatics are the TH400 (the step vans came with these behind the 4bt), 4l80e (if you can get the electronic controls, or switch to manual shift), 700r4 (some have good luck with them, others swear the cases are too weak, depends on the type of service your rig will be in), 47rh (sat behind the 6bt, should be fine behind the 4bt). Popular transfer cases are Dana 300, Np205, anything they put in 3/4 ton trucks. Popular axles are Dana 44, Dana 60 and higher, GM 14 bolts, ford 9".

The mpg these get depends on how you drive them, as well as your final drive ratio. People tend to try to keep them below 2000 rpm while cruising, if that's done you should be able to see about 25mpg maybe more.

The cost of this build can vary quite a bit. You can do it yourself, or there are shops that can do the swap for you.

With proper mufflers the 4bt shouldn't be any louder than the step vans (think your fed ex truck).

It would probably be possible to put the 6bt into your FSJ.
 
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