550 HP Version
Designed for street performance, this version utilizes oval port cylinder heads, delivers excellent low-end torque and a lopey idle with decent vacuum—perfect for muscle cars that need strong off-the-line power and everyday drivability. Built on a stroked 454 foundation, it’s a great upgrade for heavy classics.
600 HP Version
Built for street/strip performance, this version uses rectangular port heads to unlock more top-end power. It’s a high-revving powerhouse that still gets your classic moving quickly but adds serious track-ready performance and attention-grabbing sound and speed.