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I have been interested for a while in a B model build.  I have a truck that I have been looking at that is decent and intact and was running when it was parked several years ago.  Some rust but not too bad.  I plan to use this to pull trailer and haul some smaller equipment, etc. and be set up with a 5th wheel and pintle hitch.  My question is for someone that may know more about this particular model and may have gotten into this in the past is how difficult is it to change the old engine out which is the old non-turbo diesel to a more modern 300/350 hp mechanical type engine.  Just curious about wiring, clearances, engine mounting in the frame, guage connections and functionality, radiator cooling capacity and the like.  In addition was looking at changing the old quad box to a 7 or 8 speed and curious about any mounting issues, reman bracketing necessary.  Has anyone replaced the front axle with something a bit more modern and if so recommendations.  Evaluating options at this point in time and addressing the costs of these options.  Thank you for your time and input and patience with my questions.  Have lurked on here for a while but my 1st post.  I have an old RB model dump truck and have loved Macks my whole life but just something special about the B's and would love to take the project on if it makes sense and not too crazy.

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If you stick with a 237 or another model like that pretty easy I had very little problems water pump, front balancer. the 285hp. has the tipturbo so you have to deal with another air inlet line and a newer model engine with air to air I don't know how much of a modification you would have to do.

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sounds like your better off finding a truck already built. the motor is an easy change as long as you stick with a 237, 250, 285 anything e6. Matt Pfahl is the one to talk to or Kevin All. they have built many and know what fits.  the front axle gets tricky as the U bolts in a B model are a weird spacing. i know some IH and Freightliner axles will fit

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Thanks for the feedback.  I was trying to stay with the E6 family and stay away from the electronic engines.  I am not sure about changing the front axle out but was curious if I did what I would get into.  

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Don't completely rule out other engines as well. I've installed a later electronic 5.9 Cummins engine into a B-42 chassis two years ago along with a Fuller RT-14609 transmission and it's worked well with a hydraulic clutch setup. A bit lighter on the steer axle to drive from less sprung weight, and a bunch more power than the original "Magnadyne" engine. I understand the rear axle has been changed and I've not seen the truck since, but I'm told it has very good "road manners" and plenty of power. The engine was brand new from Cummins and I think 325hp. The engine computer was mounted to the side of the engine and everything but fuel lines, battery power, and a couple small things were there so connection to make it run was about an hours work with the front sheet metal removed. Aluminum intercooler piping and boots were used to interconnect the cooling system to the original radiator with very few routing/mounting problems to overcome.

 

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Dog.jpg.487f03da076af0150d2376dbd16843ed.jpgPlodding along with no job nor practical application for my existence, but still trying to fix what's broke.

 

 

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Asking about an engine swap will get you as many different answers as there are people who respond!

The old mechanical Mack engines should be pretty straightforward.  Like the man said, the water pump might have to change to make the length work out.  The turbo version of your engine (ENDT-673 variants) would be pretty simple.  The 237 Maxidyne (ENDT-675) is awesome.  But, as discussed many, many times on here, the Quadruplex (or any of the single-countershaft transmissions) might not be the best bet behind a "high torque rise" Maxi.  There are transmissions out there (Mack and others) better suited to the torque curve of a Maxi.  And, as they said, there are bigger Maxi's to choose from, too.

My '70 had the 250 HP ENDT-673C Thermodyne and an RTF-915 15-speed Fuller RoadRanger.  From the build sheet, it appeared there were quite a few parts unique to putting the fuller in a Mack...primarily in the clutch housing and its mounts.  That one also had a top-hinged clutch pedal with a cable-operated Spicer 2-disc clutch.  So, there were several pages of stuff on the build sheet that were related to putting that trans and clutch in that truck.

The '67 R611 I drove when the world was young (and so was I) had that same 250 Thermodyne in it backed by the 18-speed Quadruplex, and used the old "down through the floor" clutch pedal that looked just like the B-models we had back then.

As with any project, if you can get all the peripheral parts, or even a donor truck, it will save some hunting for the bits and pieces.

Lots of guys on here have done these swaps, and will have far more in-depth knowledge than I do!

Good luck on the project!

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"Eagles may soar, but weasels don't get sucked into jet engines."

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I will be doing a similar project as you are suggesting but, unfortunately, my experience level with these trucks is about the same as yours so i can't offer any technical info. What I CAN offer though is encouragement as support in your endeavour and, if you are still looking for info when i get to mine (which will be a year at least) I will be happy to share what I learn. You are asking all the right questions before diving in so assuming you get answers to your specific questions it should be an enjoyable and rewarding project. I picked up a 283/5spd for mine and in the process of searching for a parts truck for some of the little things missing, I stumbled on 2 more 61's in nice shape, stored inside that i bought, both way too nice as parts trucks so now i have three project trucks and am still looking for a parts truck. Can you say "slippery slope??" LOL. I don't plan to change the front axle but will be changing the rear to a more highway friendly gear and air ride. I hope you have better luck than I did in your search for information. I will be following along and i  hope that you get some answers that I can learn from as well. Good luck and enjoy your project

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