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To say we came away impressed by what we saw during our visit to PAR Racing Engines in Spartanburg, SC would be an understatement. Shop owner Scott Duggins has built quite the engine and machine shop with capabilities to do just about everything in-house. Plus, he’s got the manpower to crank out nearly 7 engines a week!
One of those builds underway at PAR was a ProCharged 557 cid big block Chevy engine that was just getting prepped for assembly while we were there. Scott was kind enough to give us the full details of what will go into the build.
“This is one of our most popular combinations,” Duggins told us. “We build these things from 540 cubic inch all the way up to 588 cubic inch, and I’ve had a lot of success with them. On a blow-through carburetor, we’ve got the fastest door car and dragster in the country now with these things.”
The build Scott and his team had coming together is a 557 cubic inch version of the big block Chevy setup and starts with a Brodix block.
“We start off with a Brodix hipped block with a 4.500” bore,” he says. “We leave the sleeves up about 0.004” so we machine the deck around the sleeves and we use top fuel hoops, which we make here in-house, to seal the head gasket. That’s some of the biggest machine work that’s got to be done sealing these things up. We put the receiver groove in the block and we put the hoop in the head.”
For the cylinder heads on this big block Chevy, Scott turns again to Brodix castings and does all the machine work and finish work in-house at PAR.
“We do all the machine work here in-house, so we cut them and we’ve got our own chamber that’s really worked well for us,” Duggins says. “We always o-ring the exhaust. We have PAC do our springs custom for us. We usually use Manley or Xceldyne valves and have good luck with both of those. We also use BAM lifters, tool steel tip pushrods and adjusters and steel rocker arms on these builds, which would be different than a lot of your bracket-type stuff or lower-end stuff.
“The port work stuff is something we’ve come up with here in-house that’s really helped with the performance on these things. We do them on our CNC. We’ve got a four axis that we do our blocks on and we’ve got a five axis that we do our heads and manifolds on.”
With machine work on the block and both heads finished up, Scott then gets to put all the components inside, and he only uses quality stuff.
“We use Callies cranks. I have great luck with Callies cranks and we use GRP rods,” he says. “We actually have Wiseco custom make our pistons for us. This is a piston that throughout the years I think we messed up enough of them to figure out how to make this one right, which Wiseco does. We have great luck with the Wiseco stuff.
“We also use ProCharger and some Vortech stuff and have pretty good luck with both of them. It all depends on the build. They both make something similar, but for different applications.”
On the PAR Racing Engines dyno, Scott says this engine combo has made as much as 2,860 horsepower. He’s also had customers make over 2,000 horsepower to the rear tires on other shops’ hub dynos. This engine combination is an excellent choice for customers looking to be competitive in Top Sportsman and Top Dragster classes.
“That’s where these fit in because we run a blow-through carburetor,” Duggins says. “We do have injectors that we run on some of them, but most of them get a blow-through carburetor. We worked with APD a lot on fuel systems for our blow-through carburetors and we’ve made over 2,800 hp with a blow through. That’s pretty good.
“It’s user friendly with a blow through. A lot of guys don’t know about the fuel injection stuff and they’re intimidated by it. We try to make it simple, and we actually have one of these in drag-and-drive with Devin Vanderhoof – he’s got turbos, but basically the same build that he holds the record with for drag-and-drive. He drove it over 2,000 miles and put 67 laps on it.
“Throughout the years, we’ve beat on this combo enough to know what breaks, so we just try to fix what’s going break and what might be the next thing to break. We have a number of these engines out there, both with turbos and ProChargers. It’s basically the same build with a cam change a lot of times and a compression change, but it takes the same basic components that we’ve had good luck with, whether it be a turbo or a blow-through setup.”
Engine of the Week is sponsored by PennGrade1, Elring – Das Original and NPW Companies. If you have an engine you’d like to highlight in this series, please email Engine Builder Editor Greg Jones at [email protected].
