Well, a little over a year ago I had absolutely had it with that P.O.S. Turd of a 500 HP Detroit 12.7L. It was a 1997 model. Yanked it out of my truck and dumped it outside after 71,000 miles on a major inframe. Shoveled in a N-14 Red Top 525 HP and absolutely love my truck. LOVE IT. That Detroit was a turd from day one. This Cummins will run all over it. Won't quite get the fuel mileage the Detroit did, but at least I don't have to work on the damn thing. You will have to replace some N-14 injectors now and then. If you have some shop do it on the road, its expensive. But I have my local injector shop do them for about $90 a piece and I do the R&R.

 

What went wrong with your detroit? My dad had around 1.5 million miles before the inframe, and the only reason that was done was because the coolant wasn't being changed regularly. Ate a hole through the liner.

Other then that it was a fantastic motor, only other problem is it started rough in winter.

 

I would react the same way based on my bad or good experience with something. I know the det's w/ the 500 hp were blowing turbo's like crazy. mine was mfg in 94' titled in 95' 11.1 60 ser & still going well over a mil miles. in cold weather is does shake rattle knock & cough before starting, but after a couple minutes it is fine. my ole dispatcher bought a 200 pete w/ a n-14 cummins red top & after putting a few thousand in new tires, alignment, e.t.c it blew a rod ride thru the side of the block in g.r. MI. I went back with him to haul his truck & trailer back home. as far as the newer engines, or trucks. I dont trust any of them like I do my own. after driving it for over 10 years, I know what to expect.

 

Turbo after turbo after turbo after turbo, then head after head after head after head. 6 injectors twice. (didn't need them but was at shops mercy on the road).

I did drive it 1.2 million miles. Kept losing head gaskets and no one could ever figure out why, not even me. I was an ASE Master Truck Tech for years. It used oil from day one - 1 gallon every 2,000 miles from new and even after the major overhaul. It never ran well - never pulled well and never got any better than 5.6 mpg. Over those miles, I had to replace 9 turbochargers and 2 reman heads and 7 head gaskets. It lost 2 head gaskets and 2 turbos in the first 100,000 miles and Detroit would do nothing about it.

The big Cummins runs circles around the Detroit and gets 5.5 mpg doing it. I don't run 60 mph - ever, so it could be better. Most of my driving is 75 to 80 mph.

 

Was it under 500K..

My Detroit didnt ask any questions, they just got to work.

 

If I had this experience with a det. I would never own one again. it appears that whenever something is made with quality, the mfg always finds a way to screw up it's reputation by soon after making inferior parts & products. I still have my original turbo. 98% of my truck components are original. I still get 6-61/2 m.p.g. my truck uses or leaks 3 gal oil in 12,000 miles. but well after a mil miles I cannot complain.

 

What was involved with the change over? Did you have a donor truck with all the electronics? Thanks

 

I bought a rolled FLD that was a year older than my truck. It had 940,000 on it and I bought it for $5,500. I did an out of frame on the Cummins, dropped it right in to the Classic and plugged in the wiring harnesses. I had to do a small bit of rewiring to get the cruise and jakes working but that was it. Next summer, I'm going to have to put a bigger radiator in it. I pulled out a 500hp 12.7 Detroit, so the radiator should have been plenty big enough, but its not. I have a hell of a time keeping it cool on a hard pull, I have to just back out of it and run up a hill about half throttle. It still pulls hills faster at half throttle than the Detroit did wide open.

All in all, it was an easy, direct swap.

 

How about the engine mounts were they the same? Or you swapped them from the fld? Sounds like it wasn't to hard. I was worried I would have to swap the harness from one truck to the other.