Older diesel SUVs are a sought-after and desirable breed, but what kind of SUV should one buy? Excursions have plenty of room but often come with the troublesome 6.0L powerplant; Jeeps aren’t full-size, and older Blazers and Suburbans can only be bought with tired old 6.2L or 6.5L engines. But what about a lightweight, short wheelbase Blazer with a Cummins? Doesn’t sound too bad, does it?
As it turns out, lightweight, short wheelbase Blazers can’t be purchased with a diesel (sorry) but that didn’t stop California resident Steve McConnachie from building his own. It started when he acquired a ’95 Dodge that was in bad shape, with more than 286,000 miles on it. Although many parts of the truck were shot, the driveline still looked good, so McConnachie decided to turn his Cummins-Blazer dream into reality.
The Blazer part of the equation came in the form of a well-used ’84 model. After some eyeballing, McConnachie removed the body from the Blazer, set it on the frame of the Ram, and then moved into the measuring stage. He had to be careful how much he cut out of the Dodge frame to fi t the Blazer body; in the end, a full 26 inches was removed from the Dodge chassis for it to work with the ’84 Chevy.
Now, just because the Blazer is a body-swap doesn’t mean the project was easy. We’ve seen a lot of hackjob swaps that are just huge body lifts on stock frames, but McConnachie took a lot of time to integrate the body and make the Blazer look as factory as possible. For starters, he fabricated all ten body mounts to put the Blazer body on the Dodge frame, which was especially challenging since the Blazer and Dodge frames were of very different widths. He also made modifi cations to the rear shackles, so they’d tuck nicely under the rear of the SUV. The biggest challenge was the front end, though, where he had to fit and mount the radiator, intercooler, and all the other assorted hardware to keep the big Cummins alive.
With a Blazer-Cummins creation sort of coming into focus, there was still one big issue: It would be painfully slow. Even with the weight reduction to 5,200 pounds, the stock 160hp 12-valve wasn’t going to set any records, even in the diesel Blazer category. Since McConnachie had already done so much of the work himself, he decided to tackle the engine and transmission too. The 5.9L Cummins long block was still untouched as the owner took the “let’s hope it holds” approach to making power. The P-pump, on the other hand, received a good amount of modification in the form of 4,000rpm governor springs, a Mack rack plug, and .022 delivery valves. The fuel plate was also removed, and timing was set at about 20 degrees. McConnachie knew he wanted his Blazer to be responsive, so he decided to go with compound turbos, using a 57mm S200 for the top turbo and a 74mm charger on the bottom. Both turbos were junkyard finds taken from Caterpillar engines, and McConnachie built the piping himself.
McConnachie’s work also made its way into the transmission, where a TransGo shift kit was installed, along with a Sonnex input shaft. The 47RH transmission was also upgraded with a stronger 48RE rotating assembly, and new clutches were added. With the responsive turbocharger setup, a super-low 1,700rpm stall converter with a custom stator was installed to give the Blazer lots of power both in and out of lock-up.
When his project was completed, even Steve McConnachie was a little surprised at how fast it was and how much power it made. He has dynoed the combination at 574 hp on fuel, and 625 hp to the wheels with a little nitrous in the mix. With a set of drag slicks, the Blazer has clicked off 11.80s in the quarter mile on fuel, and 11.40s on nitrous. McConnachie even reported that he got 21 to 23 mpg while cruising from California to Iowa. With such impressive all-around performance, could Cummins diesel Blazers be the next big thing? Hey Steve, how about building us one? DW