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More Power
04-09-2025, 14:01
What is a "Squarebody"?

This term arrived about 2010 or thereabouts. The mostly younger truck enthusiasts named the 1973-1987 GM full-size pickup trucks a "Squarebody". The mostly blocky design is somewhat aptly named. My first diesel pickup was a "Squarebody", a 1982 GMC Sierra Classic, equipped with a 6.2L diesel. You can still find images of that truck in our books and other web pages here in TheDieselPage.com, which contain a lot of information about that era trucks and its original diesel engine.

However, we're also covering Duramax and Allison swaps into the Squarebody trucks, and this forum thread will become a clearinghouse for Squarebody trucks and Duramax swaps. Thanks for visiting! Feel free to post images or links to Youtube videos about your Squarebody. To begin, let's have a look at a Suburban Squarebody I found at a diesel dyno event some years ago. While not about a Duramax swap, this Suburban does contain some useful information about a diesel swap.


https://www.thedieselpageforums.com/tdpforum/attachment.php?attachmentid=7947&d=1744232028

I was at a diesel event a few years ago, where I saw a really cool Squarebody diesel swap. I was particularly interested in the intercooler installation, as I'd heard sometime before this that it was pretty tight trying to fit a full-width intercooler in behind the grille. So, while this Suburban didn't get a Duramax, it did get a full-width intercooler!

https://www.thedieselpageforums.com/tdpforum/attachment.php?attachmentid=7946&d=1744232028

Owner: Chris Preputin
Truck: 1986 Chevy K2500 Suburban
Engine: 1993 Dodge 5.9L 12-valve Cummins

The Spearco/Turbonetics intercooler just squeezes into the available space behind the grille.

https://www.thedieselpageforums.com/tdpforum/attachment.php?attachmentid=7945&d=1744232028

I didn't measure the exact clearance between the bars of the grille and the face of the intercooler, so I don't know if an A/C condenser would fit, but I suspect that a way could be found to accommodate the A/C. In any event, this Suburban was a one-owner (family), recently re-painted and modified to include a Dodge Cummins, and was very well done. I'm glad the GM square-body trucks are making a comeback!

More Power
05-09-2025, 08:32
We've been involved with quite a few GM Square Body (1973-1987) pickup truck projects that received a Duramax swap. Here's a recent contact with John Murray, who is using our mounts in his projects.


The mounts are great we just did a 85 K20 with a LBZ. I am now building a K30 with a LB7 - John Murray

https://www.thedieselpageforums.com/tdpforum/attachment.php?attachmentid=8003&d=1746803986

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Also, we have a article here in The Diesel Page about one of the very first Squarebody trucks to get a Duramax.


1987 Chevy C30
Duramax Diesel Conversion

Bringing new life to an older truck is more than just a way to save a ton of money. A surprising number of members keep the same vehicle for decades, and want to do all they can to keep it on the road. Converting the drivetrain to Duramax/Allison power has become a popular upgrade, which increases the vehicle's capability and value. Member Kean Clark was working his way through a 1987 Chevy C30 restoration and Duramax swap project, and we wanted to show you his project.
https://www.thedieselpage.com/features/ClarkDMConversion.htm

TDP Duramax swap mounts: https://www.thedieselpage.com/conversionmounts.htm