If you're restoring a Porsche 356 Super 90 or upgrading a standard 356 engine, the cylinder head is a critical component. The Super 90 head is known for its larger valves and improved ports, which boost horsepower. But finding the correct part number can be confusing due to variations over production years and aftermarket reproductions. This guide covers the OEM Porsche part numbers for Super 90 cylinder heads, how to identify them, and what to consider when buying.
Understanding the Porsche 356 Super 90 Engine
Introduced in 1960, the Super 90 (engine code 616/15) was a high-performance version of the Porsche 356. It featured a 1.6L engine with a 9.0:1 compression ratio, different camshaft, and most notably, larger cylinder heads. The Super 90 heads have larger intake (39mm) and exhaust (35mm) valves compared to the standard 356 heads (36mm intake, 32mm exhaust). This improved breathing resulted in 91 horsepower—a significant bump over the standard 75 hp.
Why the Part Number Matters
Using the correct Super 90 head number ensures proper valve size, combustion chamber volume, and port shape. Incorrect heads can lead to compression issues, valve clearance problems, or poor performance. Moreover, some aftermarket heads claim to be "Super 90 style" but may not match OEM specs. Knowing the exact OEM part number helps you source a genuine replacement or a quality reproduction.
Official Porsche Part Numbers for Super 90 Heads
Porsche used two primary part numbers for Super 90 cylinder heads during production:
- Left (driver's) side: 616.104.105.00 or 616.104.105.01
- Right (passenger) side: 616.104.106.00 or 616.104.106.01
The suffix .00 vs .01 indicates minor casting revisions. Both are functionally identical. These numbers are cast into the head near the spark plug area. However, many used heads may have the numbers worn or hidden by dirt.
Identifying Super 90 Heads Without a Part Number
If the casting number is illegible, you can identify Super 90 heads by visual inspection:
- Valve size: Measure the intake valve diameter. If it's approximately 39mm, it's a Super 90 head. Standard heads measure 36mm.
- Chamber shape: Super 90 heads have a smaller combustion chamber volume (around 42-43cc) to achieve 9.0:1 compression. Standard heads are typically 49-50cc.
- Casting feature: Look for a "S" or "Super" mark on the top of the head between the valve springs. Many genuine heads have this.
- Spark plug angle: The spark plug hole is angled differently than later 912 heads. Compare with a known Super 90 head if possible.
Differences Between Early and Late Super 90 Heads
Production of the Super 90 ran from 1960 to 1963. Early heads (1960-1961) had a different exhaust port shape with a separate stud for the heat exchanger. Late heads (1962-1963) used a revised exhaust port design that integrated the heat exchanger flange. If you're building a period-correct engine, verify the head casting date code (found near the part number) to match your car's year.
Buying a Super 90 Head: What to Look For
When purchasing a used Super 90 head, inspect for the following:
- Cracks: Common between the valve seats or from the spark plug hole to the exhaust port. Use a bright light and a magnifier. A quick pressure test is ideal.
- Valve guide wear: Worn guides will cause oil burning and poor running. Check for excessive movement.
- Seat condition: If the head has been cut multiple times, the valve seats may be too thin to recut. Measure seat width.
- Stud threads: Damaged studs can be repaired with helicoils, but check for cracks around the holes.
- Casting numbers: Confirm the head has the correct Super 90 part number. Many standard heads are misrepresented.
New and Reproduction Options
Genuine NOS (New Old Stock) Super 90 heads are rare and expensive. Several manufacturers produce high-quality reproductions:
- Porsche Classic OEM: Porsche has reproduced some 356 parts, but Super 90 heads are generally not available new from Porsche. Check with authorized dealers.
- Aftermarket brands: Companies like AA Performance, Motor Meister, and PerTronix offer aluminum or cast-iron heads that match Super 90 specs. Be cautious: some have slightly different port designs or require different gaskets.
- Core exchanges: Some parts suppliers offer rebuilt Super 90 heads if you send in your core. This can be cost-effective if you have a cracked head.
Where to Buy (Without Mentioning Marketplaces)
- Specialty Porsche restoration shops: They often have used or new stock heads. They can also inspect and guarantee the head.
- Vintage Porsche clubs: Many members sell parts. Join a local PCA chapter or online forums.
- Engine builders: Professional 356 engine builders (like Willhoit Auto Restoration or Precision Matters) can source correct heads and may recoat them for durability.
Always ask for photos of the actual part number, valve face condition, and whether the head has been pressure tested. Avoid buying without verification unless you can return it.
Installing a Super 90 Head: Practical Tips
- Use the correct gasket: The head gasket for Super 90 is different from standard 356 heads due to the smaller bore? Actually, all 1.6L 356 heads use the same bore (82.5mm), but the Super 90 gasket may have a different fire ring thickness. Use a quality gasket set from a reputable brand like Victor Reinz or Elring.
- Check pushrod length: The Super 90 camshaft may require different pushrod length. Measure before assembly.
- Valve lash: Set intake to 0.006" and exhaust to 0.008" when cold (factory spec). Adjust with the engine fully assembled.
- Cooling: Super 90 heads often run hotter. Ensure the oil cooler is in good condition and use a proper thermostat.
Final Recommendation
For a correct restoration, source a genuine Porsche Super 90 head with part number 616.104.105.01 (left) and 616.104.106.01 (right). If originals are unavailable, choose a reputable aftermarket head that explicitly states it replicates OEM specs and have it inspected by a 356 specialist. Avoid generic "performance" heads that claim to fit but may require modifications. The investment in a quality head is worth it for the performance and long-term reliability of your Porsche 356 Super 90 engine.