Stock 35.5mm intake, 32mm exhaust valve sizes, ported for maximum air speed and flow. This means that they are custom built to your engine and driving requirements. Not a cheap set of universal heads like most people sell. We offer both high air speed for maximum low end that is superior over stock yet provides maximum flow available, providing a much wider power range than anyone else in the business. Most porters do not even have a way to measure the air speed (velocity) or the amount of vacuum at the carburetor like we do. They are only looking for maximum flow to achieve top RPM power, which normally destroys the air speed, reducing the low RPM torque, tune-ability and driveability of the vehicle.
This is fine if it is for an all out race car only application with super close ratio gears. However, is ridiculous for a normally driven car. We maintain the balance for YOUR engine's needs (piston speed, cam, carburetion, exhaust, etc.) and the type of driving you will be doing. For this reason we are not able to mass produce sets of heads and do not have them on the shelf. They must be made after we know your engine's needs.
Next, we never cut out the intake guide boss as it is required to properly hold the guide in place so it can provide many, many more years of trouble free service. In other words, more return on your investment. The exhaust guide boss is streamlined just enough to provide proper flow without the radical loss of air speed that occurs when it is totally removed. Naturally, it is far more work to port around the guides as compared to simply whacking them out and flap polishing them like most (wham bam) porting people do. Port sizing and location of material removal is extremely critical in providing power and driveability.
Our experience with dyno and street testing, and flow work in these areas over the last 30 years, exclusively on air cooled VW's, is unsurpassed by anyone in the VW head business. All Berg heads receive our 3-angle valve job where the seats are all moved out to the outer edge of the valve with multiple angles (provides more flow), intake valve ground with multiple angles and seats properly blended from the 60 degree cut. All keepers are ground so they do not touch one another providing complete locking from retainer to the valve eliminating the wear on the keeper grooves.
Valve spring shims are installed in accordance with carbs, RPM range, cam lift and required spring tension. Berg chrome moly heat treated retainers and our dual springs (POTL) are used exclusively. Bored to the cylinder size and Semi-Hemi cut (unless you specify not to) to your engine's requirements, completely lubed, assembled and packaged in plastic bags so all you need to do is install them and follow the exclusive Berg copyrighted instructions.
If not in stock, delivery is from one to three weeks and will depend upon our work load.
Note: All Berg GB 865 and larger ported and polished heads are done with the manifolds bolted together on the heads. Yes, far more time consuming and costly, however, this is the only way that any head/manifold can be properly matched ported. Only Berg manifolds are used because all others I have seen have bolt holes in the manifold to the heads which are far too large to re-install with any type of proper re-alignment once they have been removed. Furthermore, few other manifolds provide proper flow and air speed, or are not designed properly to provide all around performance as ours are. Manifold ship weight is not included with heads that have manifold labor.