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Help understanding the Cummins Big Cam 2/3/4, 300/350/400/855 etc???


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By erich.vongeist - Sunday, September 06, 2009 7:52 AM
Hi guys,

I need some help understanding the Cummins Big Cam engines. The numbering system and ratings are confusing. I downloaded the .pdf file from the library and read it but I am still confused. I am correct in thinking that the NTA-prefix means that the engine is aftercooled? The NTC- has a centrifugal water pump? Are all BC2's NTC300's? Is the "350 cummins" the BC3 NTC350? What about the NTA855? I saw it rated at as much as 525 hp.

What are the specs and ratings of these various Big Cams and what is their maximum hp/torque?

Thanks, Erich

By Geoff Weeks - Sunday, September 06, 2009 10:06 AM
N= 4 valve head

T= Turbo

A= aftercooled

C= "custom" rated (doesn't really mean much)

 They stopped useing the "A", as most of their turbo engines from the 70's on were aftercooled.

    Small vs. Big  cams:

   Cummins truck block went thru many changes. It had small bores then was bored out to 855 CID... They were haveing trouble with cam lobes wearing, and incressed the size of the cam allowing for longer "ramp" times on the lobes . So to tell the older 855 from the newer block, they called the new block the "Big Cam" as that was the main differance between it in the older "small cam" engine. Each time they made a design change to the "big cam" it got a new number. Hence big camI, II, III etc.

  There are changes, some of which can be retro-fitted to the older blocks, some can not.

   There are different rateing for each family... you can have a big camII that is 400 hp or a big cam IV that is 315 hp... it doesn't refer to the Hp setting but the design level when biult.

  

By erich.vongeist - Sunday, September 06, 2009 10:14 AM
Ok Geoff that makes sense. But here's another question. What is the maximum hp you can get out of the BC3 without ridiculous modifications(like for sled pulling)? How about the BC4? Do they both have the same Holset turbo? Is the BC4 still mechanical?

Thanks,

Erich

By Geoff Weeks - Sunday, September 06, 2009 10:32 AM
They had a 475 twin turbo factory rated engine.( automotive)... guys are easly getting 600 hp oout of that block without doing too much too them. But 400's are easyer to find and cost less. For the most part... Buy the truck, not the engine rateing... You can change that down the road if you have money and feel the need... 1st make sure the truck is going to make you money, then worry if it has enough power (with in reason). Moved my 1st 115k load from Chicago to Ft Sask. (Via Butte MT), AB with 315 hp.  I'm not saying buy a IHC 450 2bbl tractor and try and make a liveing... but you will be far ahead if you buy a good truck and can drive it, makeing a living then decide what you would like to, and can afford to, change.

  You don't want to jump trucks too often... Everytime you buy a new truck, you have to get rid of the old, and hopefully you got to know what shape it was in.... Then you get a new truck and have to start in all over again. No matter how well you look things over, there are going to be problems to repair... and if you keep jumping around you never get ahead of it.

By Geoff Weeks - Sunday, September 06, 2009 10:54 AM
erich.vongeist (9/6/2009)
How about the BC4? Do they both have the same Holset turbo? Is the BC4 still mechanical?

Thanks,

Erich

The Big Cam 4 and NT88 are both mechanical and are good engines esp if you don't try and get much more then 400 hp... The Big Cam 4 has the screwy low-flow cooling system, and while it does work, it doesn't handle high hp very well. Haveing said that, I ran my 1st 1 million miles with the Big Cam 4's and got over 1.3 M out of my fixed timed "315hp" that I later turned up to around 400.... Nothing wrong with them, but 400 hp is considered "low" by todays standard. You can get that in a M-11 (663 Cid) engine today..

   There are few people left who understand the low-flow system... so if you get one you'd better learn it yourself.

  I'll most likely keep my Big Cam 4 low-flow as I just replaced the radiator (and incressed the sq" size of radiator) when and if I start useing my Cab over again.

   It has been my experiance that older trucks all seam to have overheating problems... Most can be cured by a new radiator and proper maintance. Heat is the biggest killer of engines... it is tempting to put off fixing a marginal radiator (I know, I've done it) especally if money is tight and fall is comeing on.... It does fine thru the cooler months and trucking slows down in the winter... come spring you don't have the moneyto replace it.... so you try and make it thru another summer.... If your not careful.... you can ruin a block or head... ANd it isn't as easy to be carefull as you think... Climbing a grade... the slower you go the longer it takes on the grade and the less ram-air you get, the more you are dependant on what the fan can pull. Once your down to less the 25 mph there is only so much you can back-out of it and still keep moveing... If you can not find a place to pull off and let the engine cool, then start again, you can be in real trouble.... Parley's canyon out of SLC is bad for that.... you are climbing for several miles and are already 4000 ft above sea level. The cooling system on my Marmon is marginal at best... The P/O didn't take care of it and it didn't have a coolant filter on it when I bought it... I don't think he kept the additive level up on it and as such I have to really be careful... I hope to re-core soon, but the price of cores has got fairly high. No sence looking at whether its a 425hp or 400hp if you can cool it nor afford to fix the cooling system... Hard to really judge a cooling system by looking (and easy to disguise a bad one with fresh coolant) until you really have a load on it.

By Dennis Wells AKA Smiley - Sunday, September 06, 2009 11:55 AM

OK My turn.

My Pete has a Factory rebuilt Big cam 4.

At a resent Truck show somebody told me it was a 444 without seeing the engine and it has a spaghetti type lower hose setup, and it was a problem engine, I always thought a Big Cam 4 was known to be a good engine.

I knew different as mine has one lower hose.

Geoff's statement about low flow makes me wonder, What's up.

By Geoff Weeks - Sunday, September 06, 2009 12:42 PM
1st, yours has a high flow system and is aeither a big cam III or someone converted to big cam III specs... A Big Cam 4 is a good engine, it just is a little different. As I said, I put over 1 million in on mine and it did ok. If you try and get too much out of them they tend to get hot.  Low flow has little hoses going to the radiator 1" and 1.25" hoses. Your pic's show a big CamIII oil cooler so I am guessing you have a Big CAm III.
By erich.vongeist - Sunday, September 06, 2009 12:45 PM
Geoff, would you say that a BC4 or a BC3 is the better engine? Generally, if stock original, what BC would an 89 K100 have ?

Thanks, Erich

By Geoff Weeks - Sunday, September 06, 2009 12:56 PM
1989 is smack dab in the Big Cam 4 years, so I'd expect a 4. It does depend on what the Customer ordered and what was avaible at the time. Much before 1986 I would expect a 3.

   Both are good engines. If I had a 3 and had room to add an air to air charge cooler, that would be my choice...

  If you have a big enough low-flow rad, and the cooling system is in good shape, the a 4 is no problem at stock hp.... Just don't expect a low-flow cooling system to handle 500+ hp.

By Dennis Wells AKA Smiley - Sunday, September 06, 2009 12:57 PM
I will check the plate Tues.

Thanks

By Geoff Weeks - Sunday, September 06, 2009 1:00 PM
The Data plate will only tell you the CPL... It will not say III or IV.... so you have to look it up or know that Big cam IV's have low-flow and III's do not.
By erich.vongeist - Sunday, September 06, 2009 1:00 PM
So can you modify the BC4 to get 500+ hp? Does having dual intake stacks and dual exhaust help with heat buildup? What are the differences between 5" straights and 8" straights with respect to air flow/ engine response?

Thanks, Erich

By kblackav8or - Sunday, September 06, 2009 4:14 PM
Don't go crazy with stacks. Many a 400hp truck was built with a single stack. The monster stacks these days are just a style thing and don't offer anything in terms of performance. I suspect they may actually hurt it some. There is a range of size that will support your performance desires. Just remember if you are running an older truck and start hot rodding for more horsepower, other things suffer as well, MPG may actually pick up with a modest performance increase but then will go down as you put more fuel to it. Start making a lot of black smoke and you will attract unwanted attention in certain places and some expensive tickets potentially. Your driveshafts, u-joints, drive tires, rears, brakes and transmission will all suffer after you make a big boost in power. If you are going to try an make revenue with a truck, and you aren't all that experienced of a mechanic, you may want to run something a bit newer. The Series 60 DD and N14 Cummins and also some of the Cats are good reliable power and honestly until you have 2-3 years of experience, you really don't need any more power. Spend a little more on a well kept truck with verifiable maintenence that is speced out right for what you intend to do. Back to air cleaners and stacks - Donaldson has charts online which will tell you how much filter capacity and muffler capacity you need to support a certain cubic inch displacement and horsepower level. I am pretty sure there is a link in the parts and services section. Do a search.
By Mark Brubaker - Sunday, September 06, 2009 4:26 PM
an' I remember when a 350 small cam was a BIG horse...... I must be too old....
By scsiguy - Monday, September 07, 2009 2:49 AM
I remember that era also. Heck, I ran a 250/turbo up until 1998. It did everything I needed it to do as I ran a lot of state highways. Yeah, I'm sure I slowed a lot of folks down, but there were a lot of times they slowed me down also.
By erich.vongeist - Monday, September 07, 2009 5:18 AM
kblackav8or, Thanks for the advice. I appreciate it. I don't plan on "Hot rodding" my truck at all. Just tuning it for it's best performance for what I need it to do. I really just want to learn what each of the "contender" engines are capable of. All I really have right now is too much time on my hands. So I figured I would learn as much as I can.

Thanks, Erich

By kblackav8or - Monday, September 07, 2009 7:21 AM
If you are mechanically oriented you may want to start a small collection of service manuals. The Roadranger site has a lot of downloadable pdf files of the transmissions where you can learn quite a bit. TTC the same. Cummins has some but it is a pay site but many manuals come up for sale for reasonable prices on Ebay. Powell Books and Amazon.com also have some used books that come up from time to time. John Costley has posted a great deal of valuable info over in the parts and services section. Many drivers keep themselves in the poorhouse by staying in debt for stuff they don't need and fadish stuff that in 5 years people be stripping off their trucks. Surfboard sized visors and ginormous exhaust stacks are that sort of thing. Use the search function here, there are lots of threads where we have had long discussions on many subjects you might be interested in. For the more modern stuff you might look at "The Diesel Stop.com" There are a number of us who hang around over there also. For the older stuff this is the place.
By erich.vongeist - Monday, September 07, 2009 8:13 AM
Thanks KBlack,

I have quite a few pdf manuals from roadranger, DD, caterpillar, cummins and the like. I am very mechanically inclined, or should I say mechanically obsessed. For years now I have always bought my own parts for my cars and done whatever I could successfully accomplish myself. The motivation, I like doing it and I like saving money. I plan to continue this same S.O.P. with my own rig and for the same purposes. That's one reason I have been soaking up knowledge and advice on anything pertaining to trucks and trucking. I'll check out the diesel stop too.

Thanks, ERich

By Tony J - Monday, September 07, 2009 3:20 PM
Last July we went through the high engine temp problem with our Pete It jsut about drove me crazy and my mechnic think that he has less hair now than he did in June . we recored radiator and still overheated so we went to the T stats and rplaced tehm then water pump and still overheating  finally last resort we swaped direction of flow of coolant  mine was pulling return coolant back to the engine off the top of the radiator and the coolant form the engine was going into the bottom of the radiator . what is strange is we put this motor in March 08 and had zero heating problems till this yr. Delmar still trying to figure this one out .It was so bad that they even had the books out looking at the coolant flow chart .July was a diaster for sure   3 major whamies in a row drive line engine overheating then frt rear end shelled out because some idot forgot to use loctight on wheel differental case and the bolts all backed out .of case
By scsiguy - Monday, September 07, 2009 3:40 PM
Tony J (9/7/2009)
Last July we went through the high engine temp problem with our Pete It jsut about drove me crazy and my mechnic think that he has less hair now than he did in June. we recored radiator and still overheated so we went to the T stats and rplaced tehm then water pump and still overheating finally last resort we swaped direction of flow of coolant mine was pulling return coolant back to the engine off the top of the radiator and the coolant form the engine was going into the bottom of the radiator. what is strange is we put this motor in March 08 and had zero heating problems till this yr. Delmar still trying to figure this one out .It was so bad that they even had the books out looking at the coolant flow chart .July was a diaster for sure 3 major whamies in a row drive line engine overheating then frt rear end shelled out because some idot forgot to use loctight on wheel differental case and the bolts all backed out .of case





Sooo, did you get it fixed? I'm always interested in BC4's as I have one and have never had any problems - yet..;)
By Tony J - Monday, September 07, 2009 4:34 PM
yeap running like a champ temp now running about 195-200  pulling 80,000 lbs plus  other  wiose this is the only problem thatI have had with this engine since we had it put in as it was a CUMMINS RECON crate engine 400 @2100 rpm 
By erich.vongeist - Monday, September 07, 2009 4:37 PM
Good to know about the coolant/radiator issue if the truck I get has one in it. I really hope it does, sounds like a good motor.

Erich

By John Costley - Monday, September 07, 2009 9:10 PM
Mark Brubaker (9/6/2009)
an' I remember when a 350 small cam was a BIG horse...... I must be too old....

Mark,

I remember when it was the average horse, with alot of 290s, 300s, 318 Detroits, and 310 Cats out there too.Course, then there were the guys in the left lane with the 420 magnums, 475 twin turbos, KTAs, 475 silvers, 1693 425s, 3408s,ect,ect.I think watching, and hearing, all those big hammers going by while I was watching the 4 way flashers of the guys in front of me and behind me in those long nightime lines on eastcoast hills is a good part of why I would never buy a low power truck.Been there, done that, why go backwards ?,lol.John

By Tony J - Tuesday, September 08, 2009 12:51 AM
John Costley (9/8/2009)
Mark Brubaker (9/6/2009)
an' I remember when a 350 small cam was a BIG horse...... I must be too old....

Mark,

I remember when it was the average horse, with alot of 290s, 300s, 318 Detroits, and 310 Cats out there too.Course, then there were the guys in the left lane with the 420 magnums, 475 twin turbos, KTAs, 475 silvers, 1693 425s, 3408s,ect,ect.I think watching, and hearing, all those big hammers going by while I was watching the 4 way flashers of the guys in front of me and behind me in those long nightime lines on eastcoast hills is a good part of why I would never buy a low power truck.Been there, done that, why go backwards ?,lol.John

i have seen a many what truckers called the cumins 290's was a shiny 290  and if you had it set right you could eat a Cat on a hill  :D Man you talk about upset that trucker with the Cat would be cussing you out if you passed him and most of time tehy would ask you what you had under the hood  you tell them a little ole shiny 290  they would want to fight you then . AHH!!! them was the good old days of trucking  vey few DOTS in the state of TEXAS and only a couple of real chicken coops  Now look at us I am scared to sneeze cause there might be a DOT cop around with ticket book in hand .:w00t:

By erich.vongeist - Tuesday, September 08, 2009 12:52 AM
That's for sure. I would hate to get my trailer peeled like a sardine can because I was going to slow on the on/off ramp.

Erich

By Dennis Wells AKA Smiley - Tuesday, September 08, 2009 5:46 AM

Geoff Weeks (9/6/2009)
The Data plate will only tell you the CPL... It will not say III or IV.... so you have to look it up or know that Big cam IV's have low-flow and III's do not.

This is what my plate reads.

Cummins Remfg..

Year Mfg..           1989

Ser. #                271799276

Part #                    PR 39-RX

CPL                     891

Model #              NTC 400 B 03

Timing Code       BY

RPM                2100

I guess the model # tells me it is a 400 Big Cam series 3

By Geoff Weeks - Tuesday, September 08, 2009 6:18 AM
Yeah, I guess so... I'd have to find my CPL book to tell exactly what it is. May be Glenn remembers...

 

 Ok found the book... 891= Big Cam III 400 fixed time AFC ( air fuel control) type pump. 1989 cert by EPA

By Dennis Wells AKA Smiley - Tuesday, September 08, 2009 6:51 AM

Thanks

Now at least I know what engine I have, it has performed perfectly to date.

By Geoff Weeks - Tuesday, September 08, 2009 7:05 AM
I think you will be happy with that engine for a long time... The only inprovement  ( and hardly necessary) would be replace the water aftercooler with an air to air.... basicly makeing a Mechanical "N-14" out of it.
By erich.vongeist - Tuesday, September 08, 2009 9:30 AM
Well thats good to know about the air to air upgrade. Is that what the difference is between the BC3 and BC4?

Thanks, Erich

By glenn akers - Tuesday, September 08, 2009 12:31 PM
My CPL book dont tell me if BC3 or 4 but that year it should have been a 4. The serial # there leaveing out one of the 9s for a serial # i can not get any info from cummins quick ser. So what i would say being it is a reman engine it was a BC3 built to a BC4 cpl and it kelp the BC3 coolant system. I have did that many times for customers. Upgrade the cpl but use a older block or what ever.
By Dennis Wells AKA Smiley - Tuesday, September 08, 2009 1:16 PM
You are correct, I had a set of younger eyes look and it is.

27179276

By Dennis Wells AKA Smiley - Tuesday, September 08, 2009 1:33 PM
You got it Rick.

So I guess mine was a 3 rebuilt to 4.

Now for Erick and I, what is the differance?

By Geoff Weeks - Tuesday, September 08, 2009 2:11 PM
My CPL book does list some as " Big Cam IV but others it doesn't state what "level" big Cam it is. There are also some "RE-con" CPL's that are for older blocks updated to newer spec's  (Like the small cam magnum 400).

  The 891 calls for the older ( Big Cam III) aftercooler so it is a late update CPL for the Big Cam III's, and that explains the late EPA date. So this CPL is for a high flow cooling ( meaning pre Big Cam IV).

It calls for #3028997 aftercooler, same as CPL 588 another Big Cam III and not either of the two common Big Cam IV ( low Flow) Aftercoolers (3049534 of 3038189)

  So i believe it is a Big Cam III from the get-go.

By glenn akers - Tuesday, September 08, 2009 2:18 PM
Dennis Wells AKA Smiley (9/8/2009)
You are correct, I had a set of younger eyes look and it is.

27179276

      When i enter that serial # into quick serv it says no parts info for this engine and will not print out a cpl so it was a builder and may be by a indempend builder that cummins use. DD does that also.I like this engine cause BC4 parts but hi/flow coolant system.
By erich.vongeist - Tuesday, September 08, 2009 2:19 PM
So the issue with the BC4 is the Low-flow cooling problem with overheating? The BC3 being a high flow coolant setup, does it not have the overheating issue? Can the BC3 achieve the higher horsepower of the BC4 without ridiculous mods?

And of course the Air to Air aftercoller of the BC4

Erich

By kblackav8or - Tuesday, September 08, 2009 2:58 PM
I don't know that there was a significant horsepower increase of the BCIV over the BCIII. There were mid 400's versions of both. I also don't know that there was an air to air for any of the Big Cam's from the factory. I thought that was an N14 thing. The N14 is sort of a bigger change then a series number from the BCIV but the family heritage is all there. Don't assume because it is a BCIV it has overheating problems. They have a history of them if the cooling system is improperly maintained or improperly modified. I think part of the philosophy was to achieve better temperature control, warm the engine faster, making it run cleaner sooner and also get better MPG.
By Geoff Weeks - Tuesday, September 08, 2009 3:03 PM
All the Big Cam's used water for the aftercooler... I was just trying to point out that the major differance between a N-14 mechanical and a Big Cam III were the after cooler was changed to air to air, would only be the crank bearings... I didn't mean to inply there were any air-to air Big Cams... I hope this clears that up.
By erich.vongeist - Tuesday, September 08, 2009 3:07 PM
OK, can you modify a BC3 or BC4 to have air to air? Would there be any benefit?

Thanks, Erich

By glenn akers - Tuesday, September 08, 2009 3:20 PM
kblackav8or (9/8/2009)
I don't know that there was a significant horsepower increase of the BCIV over the BCIII. There were mid 400's versions of both. I also don't know that there was an air to air for any of the Big Cam's from the factory. I thought that was an N14 thing. The N14 is sort of a bigger change then a series number from the BCIV but the family heritage is all there. Don't assume because it is a BCIV it has overheating problems. They have a history of them if the cooling system is improperly maintained or improperly modified. I think part of the philosophy was to achieve better temperature control, warm the engine faster, making it run cleaner sooner and also get better MPG.
    and another thing about the low/flow coolant system i like was it would mantaine it coolant temp better at idle in cold weather.
By Dennis Wells AKA Smiley - Tuesday, September 08, 2009 4:01 PM

My truck has never had a overheating problem or in fact any problem.

I talked with the Don Pereira who had the engine installed while he was still working the truck and it had a small cam in it, started making strange noises started a Cummins overhaul, started costing $, and decided to have the 4 reman installed.

Aaron you probably know more about the truck than I do.

Its not like you to be silent.

By Dan Bruno - Tuesday, September 08, 2009 4:46 PM
The biggest visual difference on a BC4 versus any other Big or Small Cam is the shape of the aftercooler and location of the air piping from the turbo to the aftercooler.  A BC4 has an aftercooler with a top that angles upward with the highest point at the front of the engine.  All other aftercoolers on BC3's and earlier had a peak at the center (above cyl's 3 and 4).  The BC4 charge air pipe passes around the front of the engine, while the earlier BC3's and before had the charge air pipe coming across the top center of the engine.  Personally, I love the looks of a BC4, especially a 444.

Cummins Reman pushed a Big Cam 440Plus that was basically a "latest tech" BC3 without the step timing and low flow cooling of a BC4 444.  The 440Plus' were Cummins beige and had a BC3 style aftercooler.  They were available into the late 90's, and maybe still are.

By erich.vongeist - Tuesday, September 08, 2009 4:50 PM
That's interesting to know. Hopefully if the right truck shows up with a cummins it will be a BC4. It sounds like a very good and dependable engine and capable of plenty of HP.

Erich

By Geoff Weeks - Tuesday, September 08, 2009 4:53 PM
I would also add... the size of the radiator hoses also, the 4's had the small hoses while all others had the large hoses like any other engine of that displacement.

   As far as  I know, all Automotive 4's used the low-flow system, I know there were some Industrial/marine 4's that didn't.

By John Costley - Tuesday, September 08, 2009 4:57 PM
Tony J (9/8/2009)
John Costley (9/8/2009)
Mark Brubaker (9/6/2009)
an' I remember when a 350 small cam was a BIG horse...... I must be too old....

Mark,

I remember when it was the average horse, with alot of 290s, 300s, 318 Detroits, and 310 Cats out there too.Course, then there were the guys in the left lane with the 420 magnums, 475 twin turbos, KTAs, 475 silvers, 1693 425s, 3408s,ect,ect.I think watching, and hearing, all those big hammers going by while I was watching the 4 way flashers of the guys in front of me and behind me in those long nightime lines on eastcoast hills is a good part of why I would never buy a low power truck.Been there, done that, why go backwards ?,lol.John

i have seen a many what truckers called the cumins 290's was a shiny 290  and if you had it set right you could eat a Cat on a hill  :D Man you talk about upset that trucker with the Cat would be cussing you out if you passed him and most of time tehy would ask you what you had under the hood  you tell them a little ole shiny 290  they would want to fight you then . AHH!!! them was the good old days of trucking  vey few DOTS in the state of TEXAS and only a couple of real chicken coops  Now look at us I am scared to sneeze cause there might be a DOT cop around with ticket book in hand .:w00t:

Tony,

Absolutly, but I was thinking engines left stock.Know one fella, Peter Grant from augusta, runs his own repair shop now that he's not trucking anymore, had a 290 in a 352 pulling a reefer to the coast every week.Ran side by side with 425 Cats, rebuilt it ( himself ) about every year and a half.Was a fella running a silver and green long wheelbase crackerbox, beautiful truck from GA. or the carolinas, came up to New England quite a bit.Had a 6-71 that would run with 425s, ate at least one piston a year.Last time it happened it was crossing the Portsmouth bridge at the Me.-NH. line in the early-mid '90s, he called Mel Clark and sold it to him.It was one of the only trucks Mel kept when he had his auction and moved up to the wilds of Maine.Often wondered what happened to it when Mel passed on.Had to see it in person, prettiest crackerbox I ever saw.John

By kblackav8or - Wednesday, September 09, 2009 8:45 AM
You can do air to air on any of the big cams using an N14 intake manifold. There are other things that you must do to deal with replumbing the water lines that used to feed the after cooler. I have an N14 intake and plan to do this myself eventually once I find the right charge air cooler and radiator or radiator top. Not a high priority at the moment.
By erich.vongeist - Wednesday, September 09, 2009 8:51 AM
Thats good to know about modifying the BC's to have air to air by use of an N14 intake manifold.

Thanks, Erich

By Bullistik8v92 - Wednesday, September 09, 2009 2:51 PM
Dan Bruno (9/8/2009)
Cummins Reman pushed a Big Cam 440Plus that was basically a "latest tech" BC3 without the step timing and low flow cooling of a BC4 444.  The 440Plus' were Cummins beige and had a BC3 style aftercooler.  They were available into the late 90's, and maybe still are.

We've got two similar engines at work. The trucks had Silvers in them and we repowered them in the late 90's with 855's. They are both 444 step timing engines, but are high flow cooling with the BCIII style aftercooler. Both were "new" recon engines from Cummins. One of them has been a problem child, mostly due to the Cummins dealer who warrantied the orginal issue. The other one has been great, good power, stays cool, one of the best 855's we have next to the mechanical N14's.