need to decide on engine

[gophergunner]

Well i recently picked up a 1986 GMC crew cab, 4x4 dually. It's as loaded as they came in the year, along with a manual transmission (i wouldn't have bought an auto). And considering it's an Alberta truck, it's also in fairly good shape.

Problem is that it's running with a 454 which was converted to propane in the early 90's. Not very powerful, not very efficient and fuel isn't exactly everywhere.

I'm curious if a Duramax would fit nicely into one of these trucks...? With an NV4500 it would bolt up to the NP205 t-case and still give me overdrive and handle the power.

But my biggest concern is how easily the engine will fit? I'm assuming that since a big block fits like nothing, so would a Duramax......but I could be wrong.

[More Power]

Have a look at: http://www.thedieselpage.com/feature...Conversion.htm

[NH2112]

Go with something different for which you can still find parts pretty easily - Perkins, Deutz, etc.

[gophergunner]

Well the truck in that article looks great, but one of my concerns under the hood is the a/c. That truck doesn't appear to have air conditioning, or at least doesn't appear to have factory a/c while mine does. Its a rather bulky unit mounted to the firewall for the a/c.

As for different motors, Detroit Diesel is always an option as well as an Isuzu, but I was thinking that the Duramax would have a bit better power and economy than either of those......but I might be wrong.

[Edahall]

You might also consider the legendary Cummins 6BT 5.9L. It fits into our square bodied trucks like it was suppose to be there. The AC requires a small notch to be cut out in the front part of the frame on the passenger side. Go with a 88-93 that has the VE pump unless you need more than 500 hp. It's simpler, quieter and gets better fuel economy.

Many examples here:
Cummins-6BT-5.9-Conversions

My Suburban:

[gophergunner]

You might also consider the legendary Cummins 6BT 5.9L. It fits into our square bodied trucks like it was suppose to be there. The AC requires a small notch to be cut out in the front part of the frame on the passenger side. Go with a 88-93 that has the VE pump unless you need more than 500 hp. It's simpler, quieter and gets better fuel economy.

Many examples here:
Cummins-6BT-5.9-Conversions

Thanks for the link, I'm going to check it out after work tonight.

I kept telling myself, keep it as much GM as possible when i was planning this with my regular cab, but the Duramax has so much electrical, the 6.5 isn't as powerful or reliable especially since the truck will end up with a welder and tools and such. A 2 stroke Detroit was always the dream, but again not as powerful and noisy. The 5.9 Cummins makes the most sense really. Either that or an equally sized 6 cylinder Isuzu.

[Edahall]

I would not rule out a 6.2L. With a free flowing exhaust and some mods, it might be happy behind those 4.11 rear axles if that's what your truck has. It won't be fast but it'll get the job done. And here is something to think about. A Cummins behind 4.11 axles and an overdrive transmission such as an NV4500 will be severely limited for highway speeds. You'll either need to go to 3.54 axles or install a Gear Vendors. I have 3.73's on my truck and without that double overdrive, the engine is really wound up at highway speeds.

[gophergunner]

I have a 3 speed Spicer 5831B auxiliary transmission sitting around collecting dust, right next to a divorced 205 and a Ramsey pto winch.

With a 5.9 Cummins and a 2wd 6 speed tranny it would work nicely with the auxiliary tranny. But I would have 4 driveshafts and a really long front driveshaft. But it would give me that double overdrive for cruising down the highway, along with a wide selection of really low gears.

The truck doesn't need to go fast, if anything slower keeps me out of trouble with cops. But I would like to have an engine with enough power to maintain highway speeds up hills. The 5.9 would be capable of that moreso than a 6.2 or 6.5 would.

[b1jetmech]

Know I'm a little late in response here but have to chime in.

Definitely go with a Cummins!

You will no find a more durable motor.

Stay away from electronic diesels they cost too much in parts and maintenance. A buddy of mine took 6hours to change a water pump on his Duramax. A Cummins takes 20 minutes including coolant drain just to give you an ideal.

Chase