ProCar Associates in Akron, OH, recently took on a classic HEMI build and made it into a one-of-a-kind mill. They did the complete car, which took R&D work and some special components, then it was run on the chassis and engine dyno for final tuning.
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The engine was built by another shop out west originally and had some “issues,” so when Pro Car got it they had to do a complete rebuild. It was a carbureted engine when it came in but they converted it to Hillborn injection with a FAST EFI. The cams were tuned and degreed and valves lapped as it was ready for its first pulls.
Chuck Wright, also a master welder, fabricated a very slick intake for the HEMI as well. It took Chris Wright and his crew about 12-14 pulls to finally get the numbers they wanted to see. But the final outcome looked and performed like a work of art.
“Our engine dyno allows us to perform steady state tuning through the rpm ranges. For the Hemi engine, I would hold the it at 1,500, 2,000, 3,000 – 6,000 rpm to do the fuel curve and timing,” says Chris. “Knowing our dyno is repeatable to .1% and being able to perform steady state tuning gives us the ability to optimize the fuel and timing tables. When I work in the timing table I watch torque so as I change the timing I can see if torque increased or decreased. This way I can get maximum torque at minimum spark advance.”
Once they completed the steady state tuning of the engine they performed a few more pulls where little adjustments were made. Chris says he made at least a dozen pulls, and the engine made a whopping 715 horsepower at 6,000 rpm.
Once the engine was put in the car, Chris only needed to make minor adjustments to the fuel and timing on their chassis dyno. “Having an engine dyno setup like ours sped up the whole process of tuning,” he says.
The owner of the engine lives in Detroit and it ultimately ended up in this 1968 Plymouth Road Runner. Not a bad ride for the motor city, we think.