These seasoned GM LS3 heads have finally been given a chance to breathe after a full treatment on our state-of-the-art CNC equipment. That includes porting and smoothing out of the combustion chamber on our 5-axis, a CNC valve job on our Newen Contour and getting milled to perfect flatness on our Berco.

The port work brings the intake runner volume from 260 to 290cc. The exhaust is increased from 80 to 95cc. The smoothing work in the combustion chamber leaves it with a 71cc volume. Take a close look at the spin video and photos showing unsurpassed quality of the machining work. 

We assemble these heads using:

• Manley Severe Duty intake valves,
• Manley Extreme Duty Inconel exhaust valves,
• Manley NexTek valve spring kit and retainer kit

Unlike pure head porters, we build engines. While flow numbers are useful information, we really like to see how they do on our dyno. Better yet, we want to see how they do on the track. Furthermore, we intentionally sacrifice air flow to preserve the valve guide. Who needs a head that will eventually grenade an engine due to its missing half the valve guide?

And yes, we eat our own cooking. A set of these heads were on the GMC Canyon that our 5-axis programmer ran on Drag Week. His naturally-aspirated, pump-gas LS3 produced 766 hp on our dyno.

Call us at 815-725-2727 to order a set for your car now.

NOTE:
$600 CORE DEPOSIT WILL BE REFUNDED UPON RECEIPT OF A USEABLE SET OF REPLACEMENT 823-CASTING LS3 HEADS FROM YOU.