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6.2L Buildup

Turning an old 20-Something GM Diesel Into a Modern Power Puller

Photography by Bruce Smith

Rebuilding For Power
Rebuilding the 6.2L diesel is a comparatively cheap way to have reliable and capable diesel power. Instead of paying $6,500 for a crate 6.5L short-block, you can rebuild a 6.2L and kit it with a Banks turbo for about $4,500. As a note of interest, back in 1989, GM chose Banks as the 6.2L dealer-installed turbo option, and remained so until GM released its own 6.5L turbodiesel. This ultimate upgrade for the venerable 6.2L workhorses provides as much as 60-plus hp and 115-plus lb-ft of torque, plus 10 percent better fuel economy according to Banks.

Of course, we wanted everything we could get out of the ancient '82 we bought. That meant a lot of new parts and special attention to details to give it new life. In addition to the typical engine rebuild parts, we stepped up the power quotient on our builder by installing a Banks Sidewinder turbo kit-a dealer option GM offered in the latter days of the 6.2L. The $2,100 Banks kit includes everything from the Banks Ram-Air intake with cast air-filter housing to the Sidewinder turbo with turbocharger exhaust manifold, pressure-chamber-plenum boost tube, special radiator hose, and crankcase-vent duct. It also includes a complete 3-inch stainless exhaust system with a Dynaflow muffler.

Speaking of the power from a rebuilt 6.2L, we ran our "new" Banks' turbo'd engine on the dyno at Vanderley Racing Engines in Lyman, Mississippi, not far from where Karl Hagar and Warren Spears did the overhaul. Here's what we found: The original '82 6.2L delivered 130 hp and 240 lb-ft torque. Our "new" 6.2L delivered 58 hp more than the stock engine did and 110 lb-ft of torque between 1,100 and 1,800 rpm, and 40 hp and 85 lb-ft more power at 2,800. That puts our builder engine in the same power range as the 6.5 turbo found in today's GM heavy-duty pickups.

So, as you can see, the end result of a 6.2L GM rebuild is a stout, reliable, fuel-efficient diesel that runs as good as or better than the popular 6.5L turbodiesel. We expect to get a decade or more of service from this one-and a lot of raised eyebrows when we open the hood to show off how fine a 24-year-old turbodiesel looks. You should see similar results.

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216 comments
Layne Crea
Layne Crea

I had a 6.2 that I put over 200k miles on. About the only thing I had to do to it was replace glow plugs occasionally, and change the oil. It was reliable, and you could work on it yourself. It was also a dog.

Andrew Robertucci
Andrew Robertucci

Good luck keeping the head gaskets from blowing if you actually use it.

Josh Mecham
Josh Mecham

Save some time and money and do the right thing just drop a Cummins in it enough said!

Andrew Hershfeld
Andrew Hershfeld

Calvin only reason people say that the Powerstrokes are junk after the 7.3L is cause everyone thought they could work them to death with out doing maintenance to them. Using the wrong oils, fluids, after market filters, tunes....if ya did a few minor things and didn't use a tune these engines would last a long time.

James Slykhuis
James Slykhuis

I'd love an old 6.2 or 6.5 truck, good old Detroit diesels

Joel Case Sr.
Joel Case Sr.

Got 3 6.2s and one 6.5 its a constant job to keepm runnin all 3 cummins 7.2 cat and 7.3 idi IH just maintenance

Joel Case Sr.
Joel Case Sr.

Dmax Is assembled in moraine not manufactured parts r forged and founded in japan

Gaven Kemp
Gaven Kemp

The old 6.2 and 6.5 were seriously the worst diesel motors built. I've worked on several and not only are they a nightmare, the parts are getting more scarce as well. The thing I never understood about them is why didn't they have an I/C. Would've been beneficial.

Nitish Kurup
Nitish Kurup

Should've added another Turbo on the other side aswell, would've been a class apart.

Michael Raleigh
Michael Raleigh

No they don't. Lol go research something. Literally everything you just said is wrong. The duramax is built ENTIRELY in moraine ohio by DMAX corp. which is owned by GM. The only thing Isuzu ever did was CO-DESIGN the motor with GM. I swear you people are idiots.

John McDaniel
John McDaniel

I'd own one of these over any 6.0 powerstroke that's forsure gutless powerless lasts forever tows anything and can get mpgs just not fast from a to b but definitely gets there

Hunter Davis
Hunter Davis

I have a 1991 Chevy that's begging for yall to put that beautiful beast into

Griffin Krage
Griffin Krage

An old dog not much power but u couldn't kill it

Tyler Coulson Cooter
Tyler Coulson Cooter

Got a 93 6.5td 1ton. Making 325hp 510tq gets 23.8mpg hwy. 350000miles running like a clock

Seth Esparza-Vanpelt
Seth Esparza-Vanpelt

well isuzu was a big part of the development of the lb7 but builds them? no. they are not even the majority owner of the name today

Randy Bahl
Randy Bahl

Still take my old Idi 7.3 with the hypermax turbo set up

Travis Womack
Travis Womack

I got a 84 blazer with 1 ton axles on 44" tires 6.2 around 450k still runs fine.. have a 93 dodge 1 ton 4x4 cummins its broken.. at 253k had a 95 dodge cummind blew motor at 237k yea 6.2 reliable just not most power

Jeff Kramer
Jeff Kramer

I bet it makes more than 148 horse power now. My suburban has a 6.2 and thats all it makes

Nick Fischer
Nick Fischer

more stuff like this!!!!! maybe a gm 5.7 build just to see some sweet carnage .. just more odd ball builds

Eli Jack Douglas Stone
Eli Jack Douglas Stone

Smh. That article in the last mag about "That Guy" is so spot on. So many "That Guy" comments being made.

Zachary Stein
Zachary Stein

I've got a 6.5 2500 that is my daily driver, to be honest I love it, great power and sound, rides like a dream, and does what I need it to do without a fuss.

Jeff Ragland
Jeff Ragland

I had 4 new GMC's back in the 80's with the 6.2 i loved them 26 and more MPG on the HY and i was getting 22 around town

Jesse Stone
Jesse Stone

The 6.2 was a great motor not your modern day power house but most people on here prolly dont use their trucks like trucks anyway Cant go wrong with a Detroit Diesel!

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