Cummins Conversion Kit

Big Dog Off Road Cummins conversion kit

Big Dog Off Road Cummins Conversion Kit has finally released the Cummins Conversion Kit. This group of products was designed to be sold as a “do it yourself” kit or we would be happy to provide the labor to install this as a “turn key” project. This DIY Cummins conversion kit for the Hummer H1 and HMMWV is different from competitors products every step of the way!  The Cummins engine conversion fits MUCH better than the Duramax will actually fit into a Hummer chassis cleanly.  We would also be happy to do your installation if you prefer and can coordinate shipping worldwide.

Cummins 6BT engine (5.9L or 6.7L) with turbo and engine accessories.
Allison transmission (available for $5k with no core for a completely remanufactured unit) and torque converter.
Parts of our standard Do It Yourself Cummins Conversion Kit will include:
– Engine & transmission mounts
– Engine to transmission billet adapter plate
– HD flex plate (stable up to around 750HP)]
– Transmission to stock NP242 t-case adapter
– Engine wiring harness including bulkhead connector at firewall and wiring harness all the way up to the gauges
– Dash gauges
– Transmission controller with TPS
– Air intake system
– Intercooler system (rated to 650HP)
– Complete exhaust from turbo back: 3-section 4″ mandrel bent exhaust with muffler included (or straight pipe)
– Body lift
– AC lines
– PS lines
– Coolant hoses
– Drive shafts (with 1350 Spicer joints with double-kardons).
– Main fuel tank (approx 36 gallons)
– Fan shroud
– Engine fan 

What it does not include:

– Cummins 6BT engine (5.9L or 6.7L), with turbo and engine accessories.
– Allison 1000-series transmission (available for $5k with no core for a completely remanufactured unit).


– We do not sell out components individually. We get asked all the time “can you just sell me your engine mounts so I can get going on my project?” The answer is no: every one of our components is designed to work with the other components in our kit. If you have our mounts you’re going to need our fuel tank, drive shafts, and cooling system also. Then you’ll need our wiring harnesses, gauges, etc. Add our intercooler system, intake, and a few other things and you’ve got the whole kit.

– Our wiring harness is a complete plug-and-play harness to go from the engine to the ECU (on ECU engines), through a bulkhead connector at your firewall, and up to the gauges. – 100% of these components are made in the USA! – We can arrange shipping your Hummer anywhere in the world (domestic shipping takes about 1 phone call).

– This kit ships freight due to the number and size of parts. We can ship to a residential or commercial address and offer liftgate delivery also.

– For 6.7L engines, this kit deletes the EGR system completely so, therefore, it is sold “for off road use only”.

– This product kit only supports an Allison 1000-series transmission. We don’t care about how great you think your Dodge transmission is that you got from a wrecked donor truck, we have no intention of completely redesigning our entire system geometry to accommodate your crappy transmission that doesn’t work anyway. Just buy an Allison transmission (we sell them for $5k with no core charge required, built to handle 600HP)


Whether you are a Hummer or HMMWV owner who wants to do this project yourself or an automotive shop wanting to buy a complete kit for a customer’s vehicle this is the complete product kit you will need.