Description:
These AFR cathedral port heads bring a lot to the party with their 6-bolt design. We buy these heads as porter castings and machine them to perfection on our CNCs. The shapes we impart to the ports and combustion chambers reflect our years of experience on our own engine builds.
We know what makes power and also survives the beating of competition. It's not chasing peak air flow at max lift by excessively cutting away the metal around the valve guides. Peak air flow occurs at only one instant in the cycle. Our focus is more on average air flow across the entire cycle. For spring packages with 0.650 inch max-lift, quoting a peak airflow at 0.800 inches is irrelevant.
Of paramount importance for us is that our cylinder heads don't break and wreck our engines. We therefore do not chase flow at the expense of weakening the heads mechanical integrity. That's a concern that non-engine builders don't share.
Our process for machining heads includes CNC porting and combustion chamber machining on our 5-axis. Our Newen CNC seat & guide machine does the valve job and bowl bowl blending in a single operation. As can be seen in the video below, the Newen's CNC precision simply cannot be matched with traditional seat & Guide machines and hand blending. Being engine builders, we see first-hand how well our port designs are working on the dyno. That too gives us a big advantage over pure head porters.
The results we get are as shown in the Tables immediately below.
| LIFT | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 |
| Intake | 71 | 132 | 187 | 244 | 286 | 313 | 331 | 340 | 340 |
| Exhaust | 56 | 107 | 164 | 198 | 224 | 230 | 239 | 244 | 244 |
| Key Dimensions | |
| Intake Valve | 2.165" |
| Exhaust Valve | 1.600" |
| Combusion Chamber | 62cc |
| Intake Port | 233cc |
| Exhaust Port | 90cc |
We offer a variety of valve & spring packages for these heads to accomodate both naturally aspirated, boosted applications for use with both hydraulic and mechanical cams. The standard package offers a choice of stainless steel or Inconel exhaust valves. Custom combinations are also available.
Standard Valve & Spring Packages
AFR solid stem valves with high RPM dual springs, titanium retainers, 0.650 inch max lift.
Payment Types Accepted: Cash, Credit Card, Wire Transfer, ACH
Built by people who love motorsports for people who love motorsports
