The ZZ3 is one of the most popular crate engines in the hot-rod community.
Crate engines like the GM ZZ3 350 came about largely as a result of fuel injection and emissions compliance laws. Gone were the days when the average, mechanically-inclined gearhead could build whatever power plant they desired and stick it into the engine bay. Crate engines like the 350 horsepower ZZ3 allowed enthusiasts to focus on chassis engineering, body work and other mechanical considerations instead of devoting all of their time to building the engine.
The ZZ3’s camshaft has 0.296-inch lift on the intake cam lobe and 0.318-inch lift on the exhaust. This lobe lift will yield 0.474-inch intake and 0.510-inch exhaust valve lift when used with the standard ZZ3 1.5-to-1 roller rocker arms. Aftermarket 1.6-to-1 rocker arms will net you 0.510-inch lift at the intake valve and 0.544-inch lift at the exhaust valve.
Duration at 0.050-Inch Lift
Manufacturers define camshaft duration in one of two ways: advertised duration and duration at 0.050-inch lift. Advertised duration is how long the camshaft keeps the valve open as measured in degrees of camshaft rotation, and it has almost nothing to do with performance. Duration at 0.050-inch valve lift is a far better indicator of camshaft performance since air doesn’t flow into or out of the cylinders at anything below 0.050-inch valve lift. The ZZ3’s 208-degree intake duration at 0.050 and 221-degree exhaust duration at 0.050 make it a fairly aggressive grind, comparable to The Competition Cams 08-300-8, Crane Cams 104125, SLP 51002 or GM stock cam number 10066049.
Lobe Separation Angle
Lobe separation angle is an indicator of how long the intake and exhaust valves are open at the same time, and plays an important role in dictating the engine’s idle quality and top-end power potential. A very wide (numerically high) LSA will yield a smooth idle, good low rpm torque, and increased fuel efficiency. A Narrow-angle cam sacrifices all of that for more flow and power at high rpm. As a frame of reference, the extremely aggressive Lunati 50162 race camshaft has a 108-degree LSA and a stock 1990 Chevrolet 350’s cam comes in at 114.5 degrees. The ZZ3 cam splits the difference at 112 degrees.