The Rock Truck!

This site is finally back from the dead. I have been busy over the last couple of months, juggling work and the project. The aforementioned endeavor has been the transformation of the MXSSF flagship rig, a 1984 Dodge Ramcharger equipped with a torquey 360 cubic inch small block V8 into a beastly brutal 5.9 Cummins MACHINE.

The engine was ordered from a Cummins-centric junkyard in Texas via eBay. It sat in the official MXSSF garage from July to October waiting for the right install moment. This 1100lb beast of cast iron and forged steel needed the motive coupling of a transmission and transfer case.

This was the real mission in sourcing parts.

The Seattle area is not, according to Craigslist, awash in Dodge diesel running gear. A search on Portland Craigslist revealed to me a 47rh/NP205 combo.

I was a little nervous about driving down to Sandy, OR with a tired and worn engine. The trip down was pretty easy, no issues. I bought the gear and headed back. Getting hungry, I stopped in Centralia, a hundred miles from home. Got some grub and peeled out back onto I-5. 250f is what my temp. gauge was reading. Blew a head gasket. 100 miles of stopping to relieve pressure and add water was my final hurrah for the old 360.

Engine knocking the final 5 miles home, I miraculously was afforded a prime parking spot in front of my building. Shut the bitch down and witnessed old faithful billow from the pipes.

A couple of weeks later I trailered the Dodge to the official MXSSF garage and commenced the tear down. Distinguished co-stars LaMan and E put in some real work the first two days.



It begins...

Core support exposed.





Out with the old...



Same displacement, the 360 V8 is a baby compared to the 6bt.




In with the new...



Do not forget to secure the Killer Dowel Pin...!!! If it comes loose, your gears under the timing cover may be toast!




The first two days of work saw the installation of the 6bt and 47rh/205 combo. The next month would be the tedious work. Fuel lines, cooling lines, new alternator, wiring (ripping and tearing the useless V8 spark gear), fuel sump and so on...


A couple of issues rose to the surface:


1. I had used the wrong adapter plate. I thought I had ordered a second generation plate, necessary for the 47rh’s lockup converter. I had instead installed a third generation plate and the starter would not engage the flexplate gears. Oops! Pull the trans, pull the plate, replace.


2. The 205 case shift lever sat too far forward as installed. If I were to attempt a shift to 4lo the knob would be 2 inches into the lower dashboard. A crude bout of grinder surgery cured this. I was left with a gaping hole. An internet search found me a Mr. Gasket shifter boot with chrome trim ring. Barely large enough to cover the hole. The two piece shifter was bolted together using only one of two bolts and welded at 45*, raked to the rear. Very sharp! Professional looking. All chrome was scuffed and hit with a flat black rattle can.

The Two Oh Five‘s shifter...

The pre-intercooler core support of the ‘84 leaves little room for an intercooler, electric fan and transmission cooler (stacked-plate B&M), so the trans cooler had to be mounted on the inner fender. A Mishimoto 8” fan pulls somewhat cool air through the unit, fed by 1/2 inch rubber hose. This has been updated recently; in preparation for the 2020 WABDR run I wanted to be absolutely sure that the trans was staying under 175F on the hot side. A VDO sending unit to a VDO gauge in the dash gives a good indication of sensible operating temperature.

The trans cooler has also been doubled up. There is a second, identical cooler and fan mounted under the bed just forward of the rear diff.

Second plate cooler/fan. Keep the trans cool!


Driveshafts had to be modified due to the longer length of the 47rh transmission. Rear shaft needed shortening and the front needed elongation.


Fuel is supplied from the factory 32 gallon tank to the lift pump through 1/2” rubber hose hooked to a Bean’s fuel sump. Very simple job to cut the sump in. A hole saw is all that is needed.


The 47rh overdrive and lockup modes are handled by two toggle switches in the dash. Easy hookup. Simply ground one pole of the switch and hook the other to the outer two of the three wire harness on the trans.

The Cummins swap was smooth and well worth the time. I doubled the range on a tank of fuel and it sounds fucking cool. Drop a line if you have any questions about doing this...


First firing...


First drive, to the gas station.

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