Best engine HP/ rear combo for pulling 80,000

I would be looking at a min of 400HP and up to 500HP, Cummins N14 may be a good option for you, then you can change rating to suit. I would stay away from Det engine only because there Hp is high in the RPM range (e.g 470HP cummins / Cat / Mack all produce there peak HP around the same RPM where as Det produce it much higher in the RPM) just my 2 cents others will have different opinions. but you can check what I have stated but looking at TQ/HP grapghs provided by the engine makers. hope this helps. p.s If you are loaded at 80k lbs 95% of the time then I would be looking at 450 to 500 HP, if loaded at 80k lbs say 50% of the time then 400 hp to 450hp will be good

 

Hmmm. Good question.
As far as which engine to choose, I like an engine with a very broad torque curve because I think this allows you to cruise at lower RPM (which = better MPG), and still have good power and torque available when it is called for.
Bottom line, I would go with whatever you feel comfortable with. Honestly, as few manufacturers that there are, in such a cometetive market, they are all very comparable in just about any category. Just make sure you choose one that has been proven reliable and efficient in the field, not just on paper.

Gearing, if you are going to be limited to 65, I think something in the 3.70-3.90 range may fit the bill. This also depends on what you choose for an engine.
For H.P., I would pick something in the high 4's to low 5's.
If I was put on the spot to pick something to fit your application.
Cummins ISX 500
18 speed
3.70 rears
Just my preference.
Hope this helps.
Floyd

 

Just read Aussie Dave's post. If the ISX is a little to new, then the N-14 500 would be my other choice.

 

I run 80,000 evey load and I have ISX 475/1850 with 3.55 rears on stand up 22.5 rubber. And really think the truck pulls really well. I run 65 mph at about 1450 rpm with a 13 speed trans

 

i run 80000 or close to it with an isx 475 3:58 rears 10 speed wish i had bought an 13 or 18 speed pulling a tanker

 

I really could'nt tell you mpgs I am getting because I don't check and the boss does'nt seem to care plus my egr valve is screwed up most of the time. but we do haul 80 to 85,000 alot and it does pull pretty well. but I would probably guess around the 6's we run alot of ky va nc oh in and some pa

 

even though you are going to buy used, go make friends with the fellows at your local dealership. talk to the man that helps owners spec trucks for certain jobs. You can get a lot of insite on what goes into getting a truck down the road besides big horsepower.

 

biigger the better on the hp. 550 cat 13 speed 355 or 342 rears 1100 x 22.5 tire drive it right and the mpg should be 6.5 to 8 depending on loads weather so on.
i have 03 379 550 hp 6nz 18 spd 355 1100 22.5 mpg ave at 950000 miles 6.9
320 in wb 51 step w/quick draw cover run west ave speed 63 to 65.