Any early 6.2 diesel power upgrades, or...?

[HanSoloWS6]

Does anyone know of some power upgrades for the non-turbo 6.2, or should I save some headache and look into a 6.5 turbo swap? Or maybe a D-max? It's original to my '82 1/2 ton with a 3 speed.

[68K20 x Drill]

The Banks Sidewinder certainly kicks it up a notch, and you can always turn up the fuel screw.(First you need good tune up, and an EGT gauge)

[Russell]

Being an 82, you're gonna have a couple more problems than most to boost it, particularly when it comes to the injectors.

Your 82 has what are referred to as coarse threaded injectors, because they literally have a much more coarse thread than the rest of the injectors ever used after the red block diesels. There are two types of the fine threaded injectors, short and long, and only long coarse threaded injectors.

To turbocharge one of these diesels with a 6.5L turbo, you have to run short injectors to avoid clearance issues with the turbo stuff. Unfortunately you have coarse injectors, so you have no way to switch over to short injectors without changing your heads out.

That said, a 6.5L head has the turbo pre-cups already installed, and flow more CFM than the older 6.2L heads did, so it is a worthy upgrade regardless. It also gives you the opportunity to get rid of GM's sucky torque to yield head bolts, and put some better head gaskets in.

On top of the head studs / better gaskets, I would also highly recommend a new harmonic balancer, and a main stud girdle kit for your engine, regardless of if you turbocharge it or not. They are both preventative maintenance type deals, which will protect both your crank, and main webbings from breaking / cracking.

If you do turbocharge the engine, I would recommend you look into upgrading to the cooling system from a 2000 6.5L, as it was the best GM had produced, and also look into intercooling. An ETG gauge is a requirement to make sure you don't kill your engine, and a boost gauge is a good idea as well.

If you wish to stay naturally aspirated, just switch it out with a set of fine thread j-code heads, a J-code intake, and some good exhaust.


If you decide to switch over to 6.5L, try your best to find a 93 6.5L that has a mechanical injection pump on it. It doesn't have any electrical controls yet, and is arguably the most reliable 6.5L produced. The 94ish - 96ish 6.5Ls all had problems with the injector drive module overheating and failing (fixed with a remote mount kit with a big heat sink), and the 97ish - 2000 diesels had major problems with bottom end failures due to GM's foolish idea to weaken an already weak main webbing by installing oil sprayers to cool the bottom of the pistons.

If you manage to find one of the new aftermarket AMG blocks, they are an incredibly good foundation to start with. They are blocks produced by the company that purchased the engine design and tooling once the Duramax was released, and have all of the major design problems fixed. However, make sure you confirm that it is an AMG block, and NOT an international block. The international blocks are the 97ish - 2000 blocks with the oil sprayers, and were the worst of the bunch. It can be identified by looking down the middle of the lifter valley, and looking for the trademark International symbol cast into it.

Swapping to a Duramax is definitely possible, and it has been done already, but typically costs upwards of $10 000 to complete, including the purchase of the engine.