When it comes to connecting rods, the key calculation is the strength-to-weight ratio. Always cognizant of a connecting rod’s weight, Oliver Racing Parts recently added some weight into its popular Big Block Max rod design in order to further increase it’s horsepower holding capability, resulting in the Big Block Max Plus rod.
“We’ve just come out with our Big Block Max Plus,” says President of Oliver Racing Parts Joe Moch. “It’s aimed at the high end of the market for the guys pushing the horsepower envelope. We’ve beefed up the cap of the rod, making that more robust, even beyond what our regular Max is.”
With a 55-percent increase in the housing bore to the rod bolt corner, a 12-percent increase in cap-rib thickness, and a four-times larger radius on the bolt spot face, Oliver is looking to precisely add strength without adding unneeded weight. The Big Block Max Plus will initially be offered for the big-block Chevrolet application in lengths ranging for 6.385 inches up to 7.100 inches.
Using aircraft grade 4340 steel for its rods, Oliver’s steel has been vacuum-arc degassed, so it’s higher purity steel with fewer inclusions. “It’s basically a cleaner, stronger material,” says Moch. “In addition to using better steel, over the past year we’ve been laser-marking the rods with QR codes, so there’s full traceability in terms of the heat treat lot and batch process for quality control.”
As you may have ascertained, quality is a big deal for the folks at Oliver, opting for the more involved processes if it makes for a better end product. “We’re the only company on the market doing a double heat treatment of the rods,” Moch says.
“After the first heat treatment, we machine the rod, and then we fully stress-relieve the rod after machining. That’s absolutely crucial on a connecting rod with the cyclic loads it sees. It adds about two weeks to our processing time to turn the rods around, sending them out for the second heat treat after machining. It’s costly, but it really makes a better part.”