07 2500hd Classic

[lenb]

i am needing advice. should i buy the 8.1/w allison,or 6.0 version in a 06-07? is there a big diff. in mpg or durability. i intend to keep this truck (excab). i will run 33-35 max tire od.w/2.5-3" level kit. i will also run alot of hgwy miles. theres a decent selection of 6.0's w/low miles. i will probably purchase as used certified warranty. is 15/16 hgwy realistic? thanks guy for your input. my max lease is up and i will be buying used. this time (less pymnt).i will also run a tuner, had good luck w/superchip.

[BuckFeverZ]

15-16 MIGHT be possible with the 6.0 but 14-15 might be more realistic. 10-12 would be all I would expect from an 8.1

[sonjaab]

With bigger tires, lift/level whatever and all the other cobble mods........LESS than 10 mpg.

[Shatterz]

Well words like a superchips tuner, 8.1 (496 CID) V8, 35" tires and MPG should not be used together.

 

I'd say if you don't really NEED the 8.1 the 6.0 is a great motor (so is the good old 4l80E that's behind it) and there are probably plenty of nice ones with 6.0s out there for ya.

 

Whatever truck/motor you get, your mileage will be somewhere in the low/ mid teens whatever you do. You could possibly see single digits with 35" tires and a heavy foot.

[hockeypro1411]

I've got the 6.0 and I'm running 35's and I'm lucky to see 8 mpg. I'll flirt with 9 with the wind at my back or going downhill a lot. But don't expect double digits if you're going the way of 35's.

[ATMINF]

I would say that if the price is the same get the 8.1, and it should have the Ally behind it. That being said don't expect much more than 10-12 mpg hwy with the 35's. On my 2wd 6.0 gasser I get a little over 16mpg Hwy doing a little over 70mph. The advantage of the big block is that if it has the Ally behind it it should be a 5 or 6 speed, and you have the power of the D-max. The only two things that I can think of that are somewhat of a issue with the 8.1 is that it drinks about a quart or two between oil changes, and that they sometimes have a crank position sensor that goes bad on them. (the clear other issue is gas milage, but is a BIg Block what do you expect) Other than that they are powerhouses. Also if you are going to get it tuned, get one from one of the better tuners. I recommend Charlie Wheatley, as he tuned my truck and it is great. But there are other great tuners that are on this board also. But since I have not used them I really do not have any personnal experance to say how good they are.

Of course I would also say that if you aren't going to tow alot, and are in the medium range 7500-9500lbs towing the 6.0L gasser with a good tune also is great. I really don't tow alot, and the weights that I have towed are in what I consider medium so my 6.0L gasser is just fine. ALL in all they are great trucks, and you can find some really good deals out there.