In yesterday’s PRI coverage, we found that the LT1 seems to be a big focus of many of the industry’s heavy-hitters, and the Manley Performance booth is no exception to that notion.
“Our new LT1 piston is a similar piston to the LS, but the LT engine has direct injection. We’ve essentially mirrored the stock GM direct injection bowl in the dome of the piston. The bowl creates the right amount of swirl and atomization of the fuel in the cylinder,” says Trip Manley.
Obviously, we were curious as to why they bowl area wasn’t modified from the OE design; after all, isn’t that what the aftermarket does?
“The engineers at GM spent a lot of time on this, and they got it right, so there’s no reason to change it,” Manley says.
The company currently offers a stock stroke LT piston, then another one designed for stroker applications that has a dish in the piston top. Although the piston on display did not have Manley’s traditional skirt coating, pistons offered for sale will have Manley’s familiar logo embedded in the skirt coating. The skirt coating isn’t just for looks; it allows the builder to set the pistons up with tighter piston-to-wall clearance for noise reduction. The stroker piston is clearanced to permit the use of a 6.125-inch connecting rod. There are a high-compression and lower-compression piston for both stock and stroker applications. Crown thickness is a minimum of .225-inch across the entire piston top for durability. The top ring land is located .300-inch down from the top of the deck to reduce the propensity to lift a ring land, with 1.2 mm/1.2 mm/3.0 mm ring stack.
Also hot off the forging presses are a pair of connecting rod designs for the LT1. Connecting rod length in these engines is 6.125-inch, and Manley’s familiar economical H-beam (available with ARP2000 7/16-inch capscrews) is now available, along with two versions of the Pro Series I-beam connecting rods — lightweight (615 grams) and standard weight, which comes with their heavy beam design and checks in at 700 grams. The construction of the heavy beam rods is thicker at all stress points, and are the company’s ultimate offering for strength.
“There’s a market out there for 1,800 horsepower-plus applications, and they just can’t afford to take a chance on the connecting rod,” says Manley.
LT1 lovers, unite!