The H1 hummer – a name synonymous with go anywhere vehicles. Back in 2019 we were contacted to build a show stopper H1 with a bullet proof drive train and mean aesthetics to match. Now, if you know us we love dark vehicles and big diesels – what a perfect match. Over the next 6 or so months we discussed at length what inclusions we needed and didn’t need and needed and didn’t need etc etc etc so on and so fourth etc etc… etc.


The list had inclusions like smoke machines, military grade night vision and infrared cameras, but common sense prevailed and we ended up with a stage 1 build sheet like this:
– Brand new cummins 6BT 5.9L Diesel Engine
– Built Allison 1000 Gearbox
– DCA 6BT 500HP Upgrade Kit
– Custom Brown Leather Interior by our friends at Hy-tone
– Rewire vehicle
– 2” Body Lift (to fit the tall engine mostly)
– Fuel Wheels
– 40” tyres
– Black Out Exterior Accessories
– Panel Armour

The job was massive and required the body to be completely removed off the chassis and stripped to nothingness, the Chev 6.5L turbo diesel had already been kind enough to drain itself of oil courtesy of a conrod out the sump which is what prompted this makeover. Convenient, hey?

Cummins 6BT Allison 1000 Diesel Engine Conversion Chev 4.5 Hummer H1 Arnold

As this H1 had been converted to “civilian” spec with a cream interior and 100 tv screens in the cab space, even the removal of the interior and maze of additional wires was a task within itself. It got to a point where we just stopped, sat there and went “we need to just cut all this out and start again”, not just because of the poor quality of wiring, but also due to the fact it was safety hazard.

H1 Hummer Chev 4.5 wiring 6BT cummins allison 1000
The wiring shamozzle

After we had picked sam (our weapon auto elec) up from the hospital from suffering a messy wiring aneurysm (just joking) we got stuck into adapting the factory Cummins sae2 bellhousing to an Allison 1000 sae2 housing. The Cummins is significantly longer (being a straight 6 whereas the chev was a v8) so we did some tricky machining of the factory rear case of the 6BT to remove around 60mm of length from the combo. We also fabbed a flex plate to suit all the changed lengths and bam, done. We even maintained the factory engine mounts!

Cummins 6BT Allison 1000 Transfer Case H1 Hummer
Fun fact: The 6BT, Allison 1000 and Transfer Case is exactly one Glen Length long, or in metric terms, 182cm.

Being a rare conversion in Australia (maybe even the first), there wasn’t a whole lot of info floating around. We had to contend with a right hand side steering wheel, steering box and steering shaft, which to be honest we thought was going to create issues but it actually fit really well, even with a bigger turbo.

SO here we are, around 2 weeks away from completion of the largest conversion we have done to date. This is just a teaser, we have a full run down coming soon.

Check out this Cummins 4.5L swap we did for a Nissan Patrol! This baby puts out 180hp and 830nm at its stock set up!

Cummins 4.5L Engine Conversion Into Nissan Patrol

Check out the 4.5L Cummins Conversion info page by clicking here!

Interested in reading more about our 6BT Conversions? Click here to head over to the 6BT page!

Originally posted at (DCA is our sister business)

Categories: Uncategorized


Leave a Reply

Your email address will not be published. Required fields are marked *