Just picked up an '04 with 308,000 miles. Cummins 600, NV5600 drivetrain.

My dream for this truck is:
Brand New Engine and Fuel system.
Convert to Allison 2400
Divorced 203/205(LowMax) doubler.
3.42s with e-lockers front and rear.
33-34" Tires on 18 or 20" Rims
Low to minimal lift
MPower wagon sway bars
12k lb winch

If calculations are correct, this gives me ~85:1 crawl and ~2,000rpm@80mph

 

I live in Phoenix, AZ. Anyone know a good cummins builder here?

 

I wish I could help you. Only place I know personally (and only because I made parts for them) is A-2-Z Diesel in north Mesa. Ben there is a super nice guy. But, they get mixed reviews. There are a couple different shops more in town. If I was looking for a one-stop shop and had deep pockets, I would probably go to Chuck's speed & RV center.

 

Talked to Chuck's already. All they do is buy a Jasper motor and go from there.

 

LOL, my truck has a Jasper engine in it.


Sent you a PM......

 

Sorry, wasn't trying to bad mouth Jasper. I just like to watch and even assist in my engines going together.

 

is something wrong with your engine? 300k on a cummins is like 75k on a gas engine, should be a good amount of life left... Are you familiar with diesels off road? If I had the option, I would go gas... it's just to hard to "feel" the throttle when trying for max traction with diesels...

With doublers are you planning on some massive axle shaft upgrades, that's a lot of torque multiplied.

Good luck, keep us posted on progress...

 

The engine has some blow by and sometimes won't run past 2500rpm. Having 300+k miles at 11 years makes it have almost 30k a year and it has a 5th wheel. So I assume it has run a 99th percentile life.

As for gas vs diesel, I am firmly against gas engines in a 7-8k lb vehicle. I've had several diesel vehicles before and I'm familiar with throttle response.

No doubler will work properly behind an Allison with driver's side drop. So I'm looking at an Atlas 4spd case.

I'll have a programmer on the truck and whenever I'm in 4wd it'll be on the lowest tune.

And since I'll be rebuilding the differentials anyway, I will also be stepping up the shaft size and spline count.