82 K20 4x4 Diesel swap

[82ChevK20]

Hey guys I recently purchased a 1982 K20 4x4 and as it sits it has the 350 with the 3 speed auto and I was wondering what motor would be the right route to go, I was thinking a 6.2 but I have heard a lot of horror stories about them, Then I thought maybe a cummins but I would like something that hopefully bolts in nicely and I'm more of a V8 diesel kind of guy

Anyways let me know

Thanks

 

[Blue Ox]

Here we go again....

The 6.2/6.5 engine is usually "okay" if you accept it for what it is.

If you're looking for an acceptable street driver that is good on fuel, ask your doctor if 6.2 is right for you. If you're looking for reasonable towing power (not Duramax or Powerstroke power) it could be acceptable.

If you want to go racing, forget it. If you want to enter a tractor pull. Forget it.

They will tolerate a modest amount of turbocharging. Don't expect it to be reliable beyond 200HP. They have notoriously weak bottom ends and the main webs tend to crack, leading to broken crankshafts.

However, if you keep it in perspective and don't do anything foolish, they have a reputation in fleets for being a reliable 300K mile engine.

Alternatives:

Most people opt for the 6B. I'm not a fan in this application although will readily admit they are generally excellent engines. If only they didn't sound like a bucket of bolts.

A 4B from a step van = "P" van gives comparable performance to a 6.2 and has a flywheel and housing that bolts to a THM400 or 4L80E.

I've always been intrigued by the 5.0L V-8 Cummins that Nissan used in their pickups, but I've not heard great things about them.

Any choice you make, except possibly the 5.0L, an overdrive transmission is recommended so you can use low gear ratios to gain the pulling power and acceleration, while getting decent mileage and not having to listen to those things scream. The Cummins in particular have a low RPM range and power band that makes them much less streetable without some gear splitting.

 

[82ChevK20]

Here we go again....

The 6.2/6.5 engine is usually "okay" if you accept it for what it is.

If you're looking for an acceptable street driver that is good on fuel, ask your doctor if 6.2 is right for you. If you're looking for reasonable towing power (not Duramax or Powerstroke power) it could be acceptable.

If you want to go racing, forget it. If you want to enter a tractor pull. Forget it.

They will tolerate a modest amount of turbocharging. Don't expect it to be reliable beyond 200HP. They have notoriously weak bottom ends and the main webs tend to crack, leading to broken crankshafts.

However, if you keep it in perspective and don't do anything foolish, they have a reputation in fleets for being a reliable 300K mile engine.

Alternatives:

Most people opt for the 6B. I'm not a fan in this application although will readily admit they are generally excellent engines. If only they didn't sound like a bucket of bolts.

A 4B from a step van = "P" van gives comparable performance to a 6.2 and has a flywheel and housing that bolts to a THM400 or 4L80E.

I've always been intrigued by the 5.0L V-8 Cummins that Nissan used in their pickups, but I've not heard great things about them.

Any choice you make, except possibly the 5.0L, an overdrive transmission is recommended so you can use low gear ratios to gain the pulling power and acceleration, while getting decent mileage and not having to listen to those things scream. The Cummins in particular have a low RPM range and power band that makes them much less streetable without some gear splitting.

Yes, I don't plan on doing any raconteur or anything like that, maybe a bit of towing but that would be all and the 6.2 should just bolt in right?

 

[82ChevK20]

Yes, I don't plan on doing any raconteur or anything like that, maybe a bit of towing but that would be all and the 6.2 should just bolt in right?

Stupid spell check meant racing

 

[Blue Ox]

Yes, I don't plan on doing any raconteur or anything like that, maybe a bit of towing but that would be all and the 6.2 should just bolt in right?

"Just bolt in" is a highly subjective term. But being a GM product there is decent interchangeability.

 

[82ChevK20]

"Just bolt in" is a highly subjective term. But being a GM product there is decent interchangeability.

I mostly meant for the engine mounts

 

[Blue Ox]

I mostly meant for the engine mounts

The diesels used different motor mounts and mounting brackets on the frame.

However that doesn't mean they won't bolt up to small block mounts.

See what I mean by subjective?

 

[Frankenchevy]

Which 3 speed auto? You’ll want to get the correct governor so it shifts at the correct rpm at WOT.

I’ve thought about a c10 with a 6.2, with the thought of having a square that is good enough on fuel to commute in.

I came to the conclusion that the juice wasn’t worth the squeeze. A 4bt would be a much better route over the 6.2. If you can find a decent running bread truck with a 4bt 4l80 combo that’d be sweet. Many of them have non-od trannies though.

 

[82ChevK20]

The diesels used different motor mounts and mounting brackets on the frame.

However that doesn't mean they won't bolt up to small block mounts.

See what I mean by subjective?

Yeah, I mean what all would have to be swapped and how much work would it be if I wanted it to be mostly like factory like the dash and what not?

 

[Blue Ox]

Which 3 speed auto? You’ll want to get the correct governor so it shifts at the correct rpm at WOT.

Torque converter has a lower stall speed as well.

 

[Blue Ox]

Yeah, I mean what all would have to be swapped and how much work would it be if I wanted it to be mostly like factory like the dash and what not?

The pickups in the fuel tanks are different. The motor mounts and frame brackets are different. The transmission, as noted, is different. The gauges and senders are different. If you want the factory fuel filter setup, there's a separate harness for the water in fuel and glowplug indicator on the instrument cluster. There is firewall soundproofing. The radiator is huge. There's more, but it gets tiresome.

As I said, it's subjective. Do you want to do a factory job, or would you be okay with getting it to work?

If you buy a donor truck you'll get most of the pieces with it. When I did my swap, I could buy parts from the dealer if I needed to. Except the wiring harness. I had to make that work. Doubtful you can walk into GM today and buy those frame brackets.

 

[82ChevK20]

The pickups in the fuel tanks are different. The motor mounts and frame brackets are different. The transmission, as noted, is different. The gauges and senders are different. If you want the factory fuel filter setup, there's a separate harness for the water in fuel and glowplug indicator on the instrument cluster. There is firewall soundproofing. The radiator is huge. There's more, but it gets tiresome.

As I said, it's subjective. Do you want to do a factory job, or would you be okay with getting it to work?

If you buy a donor truck you'll get most of the pieces with it. When I did my swap, I could buy parts from the dealer if I needed to. Except the wiring harness. I had to make that work. Doubtful you can walk into GM today and buy those frame brackets.

Yeah, I've been looking at a few part trucks

 

[Blue Ox]

Yeah, I've been looking at a few part trucks

Very good idea.