6.7L Turbocharged Cummins Engine

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Jessie Harris’ 1975 Chevy C10 has been passed down for generations. His grandfather purchased it new in ’75, before selling it to Jessie's father in ’78, and then Jessie got his hands on it in the ’90s once he got his license.

Almost 50 years later and that same C10 has gone through quite a few changes. In fact, the two-wheel-drive Chevy just recently earned Fastest Diesel honors at Sick Week 2023. The machine was one of only a few diesels at the event and proved to be a stunner on the drag strip. It's been known to leave the line with 50-psi of boost on tap and pull the front wheels off the ground in route to 1.1-second 60-foot times.

Before Sick Week, Harris’ truck could be spotted at Rocky Mountain Race Week and Hot Rod Drag Week on various occasions. He's been racing the Cummins-powered truck since 2015, but before that, the truck was running gas, e85 or alcohol. Its diesel life began with a 5.9L P-pumped 24v Cummins that Harris had removed from his tow truck and dropped into the Chevy. Today, it boasts a turbocharged 6.7L Cummins that turns heads wherever it goes.

The engine is built around a stock block and has a stock crankshaft, Carillo rods, and Arias pistons. The head was done by Wagler Competition Products and has a Banks intake on it, and the camshaft is a Hamilton 188/220. It also has stock rocker arms.

"For the turbo setup we went with a single turbocharger, an S484/96 with a DPS Turbonator VGT housing," Harris says. "The fuel system is S&S Diesel Motorsports, it's their 400% over injectors and 14mm race pump. The rest of the fuel system is Aeromotive.

"I got the intercooler from Real Street Performance in Florida. I wanted a big core, and most people didn't want to talk about it, but they could do it. The front cover is a Wagler unit and it's capable of driving four pumps, although I’m driving one fuel pump and one dry-sump oil pump. Not many people do dry sump on diesels, but my oil pan clearance forced me to, and I don't regret it."

As Harris continues to upgrade and change his engine setup, the tune from his EFI Live also gets adjusted. For a long time, he was making just around 900 horsepower, but Harris believes that number was turned up to around 1,200-hp during Sick Week.

The goal for Sick Week was to get under 8.70 – unfortunately that didn't happen, but Harris attributes that to turning up the engine too quickly. The engine tune is right where is needs to be, but Harris has more work to do on the chassis to pull everything together. The ultimate goal will be do get the truck over the 1,500-horsepower barrier.

Diesel of the Week is sponsored by AMSOIL . If you have an engine you’d like to highlight in this series, please email Engine Builder Editor Greg Jones at [email protected].