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4.5L Duramax

GMC/Chevrolet 1500 Diesel Report


News of a 4.5L Duramax for 1/2 ton GMC and Chevrolet trucks hit mainstream media in 2008, but rumors of the engine can be traced back even farther. The engine was originally scheduled for release for 2010 model year trucks. Unfortunately, the engine was scrapped, literally, after General Motors economic woes set in. Reports show that the 4.5L Duramax project was killed off and all the development engines were sent to the scrap yard. In 2011, reports that the 4.5L Duramax program had be reopened began to circulate, but no definitive information has been released. Here's some specs on the 4.5L Duramax we all hope to see powering GM 1/2 ton pickups in the near future.


4.5L Duramax Specs


Duramax 4500 LMK, 4.5L Duramax


72 degree V-8 Diesel


4.5 liters, 275 cubic inches

Block/Head Material:

Compacted graphite iron block (CGI), aluminum cylinder heads

Compression Ratio:

16.0 : 1

Injection System:

29,000 psi high pressure common rail, piezo injectors


Single variable geometry turbocharger


Dual overhead camshafts, 32 valve, 4 valves per cylinder

Emissions System:

Exhaust gas recirculation (EGR), catalytic converter (diesel oxidation catalyst), diesel particulate filter (DPF), and diesel exhaust fluid (DEF or urea injection)


Approx. 310 hp


Approx. 520 lb-ft.

Possible Applications:

1/2 ton Chevrolet/GMC trucks & fullsize SUVs


The 4.5L Duramax utilizes innovative features such as exhaust manifolds that exit into the engine valley to increase thermal efficiency and overall performance. The 72 degree V configuration results in narrower dimensions, allowing the engine to fit virtually anywhere that a small block Chevrolet gas engine will. The 4.5L Duramax meets tier 2 Bin 5 emissions standards while increasing fuel economy over current gasoline options. The fact that GM literally scrapped most of the prototype engines shows that this engine will likely not be seen on the production line anytime soon. GM has rumored to reopen the project, and while we hope to see it as soon as possible, we're not getting our hopes up just yet. With Ram and Nissan entering the 1/2 ton diesel pickup scene, maybe GM will have the motivation it needs to respark the concept.