Hi, I am planning to set my 68 Dodge up for heavy hauling / towing. I was planning to use a P-pump 12 valve with compound turbos to get the job done.
Recently I was talking to a guy who sounded pretty knowledgeable at a diesel shop and told him what I was planning to do. He suggested that I consider using a 6.7 Cummins instead of the 12 valve. He said that the 6.7 would make far more power for less money, be quieter, burn less fuel, and be cleaner. That all sounds great, but what would be the trade-off in reliability, repairability, and complexity?
I know very little about electronic stuff. But I do know that the 6.7 is electronic.
This truck Will be used exclusively for long distance road trips. It has to be very, very reliable.
So how feasible is a swap of a modern electronic engine like this into an old truck? What could I expect? What would I use for electronics and stuff? I did a little snooping around and I see that the 6.7's with an automatic transmission made more horsepower than the same year engine with a stick. So I would consider an auto. Would I get some kind of aftermarket computer that would run the engine and transmission?
I would be very appreciative of any advice. Thanks, Joel

I wouldn't go that route. You need the ECM for the engine and depending on the trans you use you may need a pcm for that as well. The wiring is complex and the ecm for the engine is very expensive. However if I had your money I would throw mine away. There is nothing more reliable than a 12 valve Cummins. Choose wisely.

If your into electronics and less dependability then go the 6.7 route but the 5.9 is about as dependable as they get, and you can make power very affordably without electronics. In my opinion if this is a primarily for towing or going to do a lot of towing Id stick to 300-400 hp. any trailer requiring more hp shouldn't be towed by a pick up. The engine will hold up but the Trans and diffs (pickup size) will take a beating as well
Another thought to add. I had an '83 Crew Cab I swapped a '93 inter-cooled motor into, turned up the pump timing, added some big injectors and other minor mods got very good fuel mileage and power, I replaced that truck with an '01 24 valve (electronic motor) similar power less fuel mileage. Not to take away from the knowledgeable members here but www.dieseltruckresource.com is a great site for such projects.

I'm towing the same load now with my VE pumped 12 valve 93 d300 that I will be with the 68. I can easily throw enough fuel at it to pull any load. The biggest issue I have is rolling coal if I'm not really careful, and high EGTs when I get out west in the higher elevations.

Do some reading here. Lots of guys finding ways to make the 6.7 work with stand alone electronics. 6.7 stand alone

Most people I know put the Sweptline body on a newer chassis to take advantage of the steering, brakes, and not having a 60 year old frame...

Rhino, I agree. So it's going on a 160-in wheel base 91 D350 Cummins 2wd frame. I bought that truck with no engine or trans, so I'm still wide open on engine selection.

Not much help on setting up the electronics, but have a 2009 6.7 2500 and it has been a great powertrain!

Changed the alternator and water pump at ~375,000 miles (very easy to do both) but other than that it has been trouble free and makes great power with a close to stock tune. It is EGR and DPF deleted and has been it's whole life.

It now has 428,000 miles and runs like the day I bought it with 200,000 miles. 20-22 mpg by itself and 15-17 mpg pulling a 20 ft. trailer with a car.

I was just about to start a thread asking about the 6.7. Does it have a reputation of any kind. I know the 12 valve Cummins has a GREAT one.

My Cummins guy tried to talk me into swapping my perfectly fine '01 24 valve for a 6.7. Said it was an absolutely awesome engine, AFTER you desmogged it. High praise from a decades long 5.9 enthusiast, he was a big fan of the B series long before it went into the Dodges.

You should P pump your 93 , that will wake it up but you'll still have the same rolling coal issue. That's what kept me from gettting a 12v this time around , the smoke bleaching pig part. I heard of a guy that was selling the 5.9 out of his 01 to swap in a 6.7 , I might have to look into that now that I have a truck that is old enough for emissions to not be a concern.

I'm curious when the EPA is going to put the hammer down on all the DPF deleted trucks ?

I've got a 97 12 valve parts truck with a p pump. I could use that motor in the 68 if I wanted to. But as far as putting in a p pump to replace the VE in my 93, I can't get it to burn all the fuel I'm throwing at it now. And I currently have the VE pump power screw set at almost the stock setting, and running 5 x.012 injectors. Before I put in the injectors, I had that power screw turned in 2 full turns, it was amazing how much that woke up the truck. Even when I had the stock turbo on it. If I was to crank that screw in now with the bigger injectors installed, I'd either need a bigger turbo which is going to have lag and smoke on the low end, or switch over to a compound turbo setup. Which is definitely a possibility. Or else find a 6.7 to put in there. I like the idea of the exhaust brake on the 6.7. But I could always add an aftermarket exhaust brake on a 12 valve as well.
I'm just trying to weigh out my different choices.

Lots of good info in that thread!

Thanks for that link, I actually didn't see it until now. So I tried to read some of that stuff and it is way over my head. If I do the 6.7 swap, it seems I'd need to become an electronics / computer expert.

i checked it out also as I was thinking of doing it to my new to me 98 24v truck but it's doesn't seem worth it , too much electronics andthat is what I'm trying to get away from.

Then I thought .. Hey what about P pumping a 6.7 ? .... and that is a huge undertaking, I'll stick to my 24V for now .

I found a thread written by a guy who p pumped his 6.7. Sorry I don't have the link. Basically he said don't do it, it is very, very difficult and expensive.


Edit: I found the link... https://www.cumminsforum.com/threads/6-7-p-pump-conversion-with-pics.1713274/

6.7 short block, custom pistons, with a 12 valve head?
Maybe just a 6.7 crank and custom pistons in your 5.9.

https://www.truecar.com/used-cars-for-sale/listing/3C7WRMFL6EG288623/2014-ram-5500/

You need this to set that body on

Joel, I'm currently looking for a p-pump engine to swap into my 2003. There is so much high dollar crap that fails on the new engines it's nuts. I good set of injectors for these new engines will cost you what a p-pump engine will.

I was asking myself that question as I was reading thru some of those threads.

I like the 24V 5.9 , I haven't owned a 12v. As I get older the less electronics I have to rely on the better I feel when I'm far from home.