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May 07, 2015 at 02:32 PM CST + 1 - 2
Posted by a private BulkLoads.com member.	Posted by a private BulkLoads.com member. Looking to buy my first truck old school Pete pulling 80,000 hopper in hill country going to run 13 speed what rears will I want and is big cam 400 or cat 3406 better how much horse power will I need and which moter is easiest to get hp I need

Replied on Thu, May 07, 2015 at 10:24 PM CST

+ 1 - 1

Posted by a private BulkLoads.com member.

Posted by a private BulkLoads.com member.

Lets clarify up front that you are asking for an "OPINION" and that is what I am offering. If it were me the Cat hands down. For me either 3.36 rears or 3.25 with a 13 over. You need to keep rpm down. Either way you go call Arizona Diesel Solutions if you need help, they have an ad on here. Parts are easier to find I think for the Cat. Difficult to get RPM down on the Cummins and still have power. For sure more power upgrades for the Cat and you don't have to go with aftermarket parts.

Art Pfluger

Replied on Fri, May 08, 2015 at 09:38 AM CST

+ 1

Posted by a private BulkLoads.com member.

Posted by a private BulkLoads.com member.

myself i would go with 60 series detroit.seem to get better mpg.parts are cheap compared to cat or cummins.with simple program upgrade you can up hp and mpg .if it is a egr engine you can program egr on and off at same rpm ,so system is complete but not effective,normally 1 mpg over stock and 75 more hp..each to their own, everybody spends where they want to..good luck with whatever your decision is..

Replied on Fri, May 08, 2015 at 03:29 PM CST
Posted by a private BulkLoads.com member.	Posted by a private BulkLoads.com member. The truck I'm driving now is a Detroit with 10 speed don't no hp or ratio but it struggles on hills wondering if I could get away from that

Replied on Fri, May 08, 2015 at 04:16 PM CST

Posted by a private BulkLoads.com member.

Posted by a private BulkLoads.com member.

what year is it ..and is it a 11.1L or 12.7L or 14L if nothing else the rear gear ratio is normally on door post sticker..or call dealer with vin number and get gear ratio and trans model..what rpm is engine running in high gear at 65 or 70 mph..what is normal top speed you travel at..i have 12.7L with 700 hp to ground mpg depends on how hard you run it and gross weight..in play mode close to 2000hp to ground..but keep in mind short distance short time..either 300 ft on pulling track, or 1/4 mile at a time..you can't run the big power on the street or you would burn it down..but 700 in daily driver driven right works great..if you want to know more on this call grampa at 315-534-2540

Replied on Fri, May 08, 2015 at 06:00 PM CST

Posted by a private BulkLoads.com member.

Posted by a private BulkLoads.com member.

Just for an opinion standpoint I would go with the big cam Cummins. I am personally a cat guy but a 3406 is a heavy block. If you have a big cam m-11 with a 13 sp you will be fine. Some of the guys mentioned a smaller gear which would be fine if you were running bigger power. If you are running a m-11 you might want to run a bit of a taller gear like a 3:55 or 3:73. You will be reving higher but will have more torque getting up hills.

Replied on Fri, May 08, 2015 at 10:11 PM CST

Posted by a private BulkLoads.com member.

Posted by a private BulkLoads.com member.

All mechanical motors from that era were designed to run at higher RPMs. I would not suggest any rear axle ratio higher than 3.55. Those mechanical motors were not designed to be lugged, with a mechanical injector pump you will wash all the oil off the cylinder walls, and it will cause the engine oil to become dilluted with fuel, wich will damage your bearings and other vital wear surfaces. The big cam cummings runs real nice at 2100 rpm. If it's a cat 1800 to 2100 is prime, but dont drop it down below 1500 rpm. With these mechanical motors the injector pump will determan the personality of the throttle. Talk to bruce at pittsburgh power for how to set the fuel system up, he's one of the few old timers left that specializes in this area of mechanical motors. Bruce was the best back in the day . I had a 400 big cam that he worked on in a 81 kenworth W 900, and it left all cat's in the dust. It had The infamous GEAR PUMP on it and twin turbo set up. It brings back some fond memories. Best of luck to you.

Replied on Fri, May 08, 2015 at 10:51 PM CST
Posted by a private BulkLoads.com member.	Posted by a private BulkLoads.com member. It's 12.7 but not my truck but thanks for the advice

Replied on Fri, May 08, 2015 at 11:05 PM CST

Posted by a private BulkLoads.com member.

Posted by a private BulkLoads.com member.

Quote: " All mechanical motors from that era were designed to run at higher RPMs. I would not suggest any rear axle ratio higher than 3.55. Those mechanical motors were not designed to be lugged, with a mechanical injector pump you will wash all the oil off the cylinder walls, and it will cause the engine oil to become dilluted with fuel, wich will damage your bearings and other vital wear surfaces. The big cam cummings runs real nice at 2100 rpm. If it's a cat 1800 to 2100 is prime, but dont drop it down below 1500 rpm. With these mechanical motors the injector pump will determan the personality of the throttle. Talk to bruce at pittsburgh power for how to set the fuel system up, he's one of the few old timers left that specializes in this area of mechanical motors. Bruce was the best back in the day . I had a 400 big cam that he worked on in a 81 kenworth W 900, and it left all cat's in the dust. It had The infamous GEAR PUMP on it and twin turbo set up. It brings back some fond memories. Best of luck to you."

I probably should have mentioned that driveability becomes a issue with mechanical motors when they are turned up past 600 horse. They tend to act like a 2cyle engine in a dirt bike, doggy or balls to the walls, not to good when going through a scale.