Big Cam Cummins reliability

If your going to pull heavy have at least 3.90 or 4.11 rears under her and if were talking heavy & hill country throw the idea of fuel mileage right out the window

 

Not really one to avoid actually. Depends on what HP you would like to have starting out. My engine started its life as a 1986 315 hp engine. But it now has larger injectors, bigger turbo, and the pump is built to boogie! Never had it in the dyno but, I would say I'm pushing a good 500-525 hp with it. It's my bread and butter so I pay attention to it, I would never intentionally hurt it.

 

I think it varies person to person depending intake at hand as stated. I have a friend that logs and runs a 15 deep reduction.
I run hopper bottoms and usually stay on two lane country roads so a 10 with 3.70s do me well for the task at hand.
Another fella I know has a 400 , 18spd with 3.90s and runs mostly highway

 

If you run it like these new motors you'll kill the motor, you don't really lug these down below 1500-1600.

My dad got a lifetime 1 million + miles @6.5-6.8 mpg in a 9670 cabover

 

You go with lower compression pistons.

 

From home to Tx averaged 6.5
It's doable on a BC

 

Half of those miles my dad was coming back empty so that played a part in the 6.5 figure. Pretty decent for a brick wall

 

Absolutely it is

 

You run below 1700 on a big cam and you just might crack liners off or something, that's the only reason I can figure we had that happen on the old man's 84 pete.