I have a 96 3500 4x4 flatbed with the 6.5. I need more power. Am I going to be able to make this truck pull as good as my dads 97 cummins? We have a farm and haul rolls of hay, tractors, cattle trailers, etc.. I am estimating we pull between 12 and 14k lbs. His cummins does a much better job with a load and gets better fuel mileage. Thus he likes to poke fun.
Should I be trying to build up this truck or trade to a duramax or an 8.1?
Also it would seem to me that I should be getting better than 14 mpg. What mods should I consider to give me comparable performance and mileage to the dodge?

6.5 and Cummins 6BT engine are not even in the same league. You will need some pretty serious mods and upgrades to make your truck keep up and make it reliable.

Are you getting 14 MPG loaded or unloaded? For a one ton truck, unfortunately that number is pretty average, little you can do to change that much, short of changing the final drive ratio.

By the way, who's "8.1" L engine are you considering? No diesels in Light Duty trucks that size, your not looking at something like a V10 Gas are you? Kiss your 14 MPG good bye.

The 8.1(Gas) is a very stout motor. But as stated, your mileage will be gone.

I do believe with the correct mods, your '96 6.5 will be able to pull with the '97 Cummins.

Hi Flow Air Filter, Low restriction exhaust, Reflashed ECM, & Intercooler.

Much cheaper than a Duramax.

Intercooler won't last long in large rolling hay fields. Duramax with a reprogram will work circles around the Dodge. Mileage around 16 -17 average for a farm duty version.

Intercooler won't last long in large rolling hay fields. Duramax with a reprogram will work circles around the Dodge. Mileage around 16 -17 average for a farm duty version.
Hmm... How many large rolling hay fields have you been in? I've hauled hay out of the field on my utility trailer behind my Suburban... Dang! Maybe my intercooler is gone! ):h

Seriously, this is not a concern at all.

See http://dieselplace.com/forum/showthread.php?t=10610 for some real world dyno results!

I can't compare apples to apples, as my truck is light and now pretty well modified and I don't tow anything nor do I plan to. But on the street my truck stomp's every diesel I've come across all the way up to 2005's, even one's which have been LIGHTLY modified. My friend went out and test drove a '05 PS with intentions to buy, I told him he should drive my truck before buying, so he did, and now he's looking for a 6.5 Suburban. Nuff Said, for now.

Diesel-Pro,

The only real intercooler kit offered for the 6.5L TD places the IC in what many believe to be a precarious position (myself included). That doesn't stop people from stuffing one elsewhere. See some pictures in this post http://www.dieselplace.com/forum/showthread.php?t=24084&page=1&pp=10

MP at TDP also had a Dodge Ram intercooler modified and put into his C/K Duramax right behind the grill.

Later next week my truck is going to have an intercooler installed. I liked MP's use of the Ram's intercooler, and I also liked the pictures of 24VChevy's radiator core support mods and tray for the installation of his Powerstroke IC. I showed pictures to the guy who will fabricate my setup, and the plan is to utilize a little bit of both designs. Hopefully I'll be able to spend some time in the shop while the magic happens so I can get some pics. If not, I'll still be able to share the end results.

The 6.5 under bumper cooler won't last long on the farm. Help load/haul hay on a cattle farm / 2000 acre. Our trailers hold 180 square bales. See a lot of tranmission blow outs in the summer months when people load themselves. Most hay is round bales. Maybe your burb was squatting so low in the back and the front so high you didn't catch any stumps. Not knocking the 6.5 intercooler, just isn't practical for a farm duty vehicle.I guess my farm work doesn't count. I've off-roaded with mine a lot and have no problems.

Most of the "fear" and advice about tearing these intercoolers up comes from folks who've not used them. It's mostly imaginary. You folks always try to discredit those who've actually had experience with what you're speaking against.

BTW, I use load distributing hitch equipment, so my Suburban doesn't squat. Check out some of the loaded pictures on my web site at www.schoolcraftpowertrain.com (http://www.schoolcraftpowertrain.com/) to see for your self. Not pictured there is when I hauled a 1967 John Deere 4020 (on a bigger trailer) that made for a gross trailer weight of about 10,500 lb... part of that was through a "rolling hay field", by the way.

The intercooler is tough, it is not as vulnerable as the nay-sayers want you to believe and it works. Oh, and we try to minimize the number of tree stumps in our hay fields... they're really hard on hay equipment! :rolleyes: ):h

BTW, yes my 95 Suburban 6.5 can out pull a 97 Cummins. In fact, my cousing has a 95 Dodge Cummins that is far from stock... It's had pump work done and other mods. I don't know how much power he's making, but I can out pull him as well.

Ultimately, it's up to the reader to decide who to believe, then make an appropriate decision for what you want to do.

No doubt your truck has just about every mod out there RJ, no question about being able to keep up and out run most any diesel truck made in the 90's, but yours definitely falls in the heavily modified category, which is what I prescribed JWC would have to do to get similair results.

No doubt your truck has just about every mod out there RJ, no question about being able to keep up and out run most any diesel truck made in the 90's, but yours definitely falls in the heavily modified category, which is what I prescribed JWC would have to do to get similair results.
Agreed.

And even more modification is in the works at this very moment. ;)

I just wanted to give a concrete example of what is possible so he can decide for himself what he wants to do. Then, Diesel Pro jumped in and said the Kennedy intercooler is not suitable for farm use. I beg to differ and offered examples of the use my Suburban gets...with the Kennedy intercooler mounted beneath the bumper.

No arguement with you.

By the way, I just finished loading six round bales from my hay field on a hay hauler for a family friend using that 4020 John Deere that I mentioned earlier. But then again, I don't really do any farm work around here or my intercooler would already be broken...

I used to be real proud of my 18:1 300 hp 6.5 until I got beat on a hill climb by a friend's 97 12v cummins. We were both loaded about the same gvw, I was towing a 26.5 ' Jayco camper and he had a 6 horse gooseneck with 4 horses, very close overall weight. From the time we left the house to go on an elk hunt, I was mostly in 4th gear and sometimes 5th. He was in 5th continuiously. We hit a hill about 3 miles long about 6% grade. I hit it hard, about 60 mph, 4th gear,1250 egt,18 psi boost, 3/4 throttle. He passed me like I was standing still in 5th gear with under 1/2 throttle. He was geared with 3.55 and 245 75r16 and I was running 4.10 with 35x12.5r16.5 so corrected gearing was close. Two monthes later and my 24v cummins was up and running and a comment to my friend was made, you will never pass me again! Having driven both engines in the same vehicle with the same transmission gives me some very good insight. 6.5 was quicker out of the hole and felt more like a big block gas engine, it liked to rev and power was at upper end of rpm band, 5th gear was for cruising not towing. Cummins, has to be in 4th gear and up and then hang on:D their is no comparing 350 rwhp and 850lb ft of torque to what the 6.5 had. Don't get me wrong, I loved my 6.5, but my cummins will do everything that the 6.5 could do but 1 gear taller with very little reason to shift out of 5th gear for any reason unless the road requires less speed. Towing with the cummins is just plain easy. Now to be fair, if I turn my power enhancements off, my 6.5 would have beat this 24v. The 97 manual trans cummins powered dodges outperformed their advertised hp and trq by a bunch. I have seen numerous stock trucks put down over 230 rwhp and 500 trq and they were only rated at 215, 460. Auto trucks didn't fare anywhere close however.:ro)

Just a tid bit of info, calibration spec for the Bosch inline 'P' pump in Dodge truck with auto tranny, specs the aneroid doesn't reach full fuel delivery until 36PSI Boost!!!! Not to mention this pump is the derated version used on the 8.3s and other tractor/industrial/semi engines.

Want to clarify that 36PSI? Think your off a little.

jwc's original post asks if his '96 would be able to pull with his Dad's '97 Cummins. Nowhere does it say the Cummins isn't stock.

You're telling me No? A stock '97 Cummins doesn't make 350/850.

A well modified 6.5 will run All Day Long with a stock '97.


Enough already with the Intercooler is in a bad spot/it will get damaged talk.

Can somebody come here and actually say they damaged one? Or is it all speculation. This one's getting old.


I wouldn't say RJ's truck is heavily modified. It's modified correctly. He chose the IC, Re-Flash, & Injectors. He didn't use potentiometers, springs, & bumps. Granted, it is in the neighborhood of $2500. but it is reliable.

Still cheaper than the Duramax option...

I also work my 6.5 with every bolt on mod I think is out there allows me to pull up to about 18K quite successfully which I have done with my GN trailer loaded with my Ford 535 backhoe and a little less weight on my JD 2020 & impliments, my "at risk" IC has been there for 2 years now, in just about every condition a farm truck might encounter, & even some a farm truck would not encounter (4x4 axle deep in AL & MS gumbo mud & gravel). My last dyno while less than what RJ netted I did manage to best a stock Cummins. So properly set up the 6.5 isn't as anemic as some portray it to be.

I would go with that IC setup but am concerned about how well it would stand up, you guys talk farm vehicle, thats fine. But what about oilfield here, i travel at least 200 km's/day and about 50% of that is gravel, i can't keep the same windsheild for more than a year, sometimes have to replace them 2 and 3 times a year from the flying gravel, will that IC last out here or will it be full of holes like the windshield? I frequently bottom out in the center of the truck in ruts on muddy roads, thats why i lifted my 95 6" and put on 35" rubber, didn't bottom out much after that.

I'ts more robust than some would lead you to believe, with 35" on your truck I'd say you probably would never hit, but hey you are in the oil field I'd be willing to bet you could fab a cage around it in event you got in a really deep wallow that would keep the IC safe, a lot easier than trying to stuff a grill IC in your truck, I'm running stock 265/16 and yet to bash mine in, it does get mudded up some from time to time, but I just flush from the engine side and de-mud mine.

Want to clarify that 36PSI? Think your off a little.Whats to clarify? The aneroid does not reach full travel until you get 36lbs boost pressure to it. Although a lot of shops set the aneroid to move a little quicker, so the engine is more responsive. Turning a stock '97 Cummins into a real performer can be done with an allen key, screw driver and wrench in about 10 minutes.

That must be Canadian Boost PSI.

Coincedence...

I was watching Trucks! today on Spike, and Stacey finished up Lil Red Wagon, a '99 Dodge Ram. He installed a 5" lift with 35" tires and an ATI Procharger, among other things (like the cool pistol-grip shifter). The intercooler was mounted just like the kits Kennedy (and others) offers for sale. Wheelin' through the woods... the nub of a branch on a log smacks the intercooler. To be fair, Stacey was really trying to put some hurt on this truck. He had monsterous aftermarket bumpers, and made sure they got whacked to prove their toughness.

On the highway, it was pretty obvious this truck won't come across much that could threaten the intercooler. Unless some type of foreign object is tossed by another vehicle ahead of the truck...

Should I be trying to build up this truck or trade to a duramax or an 8.1?YES!!! GET A DURAMAX!!!! Best desicion you can make.

Thanks for all of your insight! It's obvious there are a lot of opinions on the potential of the 6.5. Maybe I should have been a little more in depth about what I want. 1 I will most likely in a year or 2 trade up to a duramax.Mostly because I want to go to a 3/4 ton truck. I don't want to sink a whole lot of money in the 6.5 for that very reason. I agree with what was said about the truck being more like a gas engine. You can almost forget 5th gear unless you're cruising. I want an engine more like the cummins. However I will not buy a dodge. I was considering the 8.1 along with the duramax. I thought I should be getting better mileage than 14 since the 1 1/2 ton cummins my dad drives regularly gets 19 loaded down with tools. So with that being said I geuss I'll just try to free the breathing up a little and put a good exhaust on. See what the future holds and shop for a good used duramax or maybe new. My luck as soon as I buy used you'll see gm get the best numbers ever out of the new ones.

The important thing to remember is that you have a truck now and if taken care of it WILL do what you want. Open up your exhaust and intake get it some more fuel and some more boost and ADDDDDDD a pyrometer pre-turbo because cracked pistons, broken pistons and scuffed cylinders from tooooo much heat-sucks! You might not pull a hill as fast as a cummins or duramax or stroke, but you won't be days behind only a few seconds!:D

And if you blow that 6.5L you can always put a cummins in.

Unless you got some pennies saved for a rainy day even a used DMAX is in the high side of many wallets ability to absorb the cost I went looking and was surprised how much they still going for, if you have a sound bodied 6.5 I'd stick with it until prices come down some more on DMAXes. You won't be top dog but with some modest investment, your dogs bark will get some respect.