Header Info For MK4 Builders Using New High Performance Heads

[Papa]

Hi guys!

After experiencing issues with header fitment on my MK4 with Blueprint Engines' 347 using their new high-performance heads, I thought I'd share some of my experience and hopefully help my fellow builders through the problem of finding a set of headers that will work on your car/engine combination. Before I forget, I want to extend my sincere gratitude to George (Georgie) Arnos from Gas-N for his above and beyond support throughout the entire process. He sent me multiple sets of headers and sent an engineer to my home to understand what needed to be adjusted to address the new cylinder head design that Blueprint is using.

For reference, the new Blueprint heads, similar to Ford Racing's Z304 and AFR heads have two features that caused fitment issues with older headers on the FFR MK4. One, the angle of the exhaust ports is 1-2 degrees different than most headers were designed for. This caused the exit flange to be a bit too low and for the first set of headers I received, interference with the motor mount perch on the driver's side. Second, the spark plugs are positioned about 1/8" higher, which requires a different flange than older style headers typically have.

Now a subjective comparison of three different manufacturer's headers that I was able to try on my car.

Gas-N (American Racing):

What I liked most about the Gas-N headers was the overall design. They look really nice in my opinion compared with the straight-tube design that is available from Factory Five. The flange that Gas-N is using is the best of the three brands I tried, with the 3" bolt spacing and CNC machined openings for the plug wires. The Gas-N headers were also the least expensive of the three options I was able to experiment with.

Factory Five (BBK):

Factory Five's original design was also experiencing fitment issues, causing them to go back to BBK for a solution. I was able to try a set of the new headers and can tell you that they fit my car. They offered the most clearance of the three sets on the driver's side to the foot box. They used a 2" bolt pattern, (my heads support either 2 or 3") making the installation really hard to get the bolts in and snugged up. The BBK (FFR) headers came ceramic coated with gaskets and bolts. They came in in the middle of the price range for the three sets I tried. The flange also incorporated a high arch between the tubes, made possible with the narrower bolt pattern, that allowed for easy plug access with no issue getting the wires on. This set of headers uses the straight tube design that I think is less attractive than the Gas-N design.

GP Headers:

Back when I was at my peak frustration, I was directed to Stainless Headers. When I called them, I was told that they no longer manufacture headers, but only components for those that wish to build their own. They outsource to GP Headers for assembled sets. I put my name on a wait list for a production date. They don't stock headers, but rather build each set to order with several options available. You can opt for mild steel, stainless steel, coated, un-coated, double collectors, O2 bung placement, etc. After about a month, I received a call that they were ready to start my order and confirmed all my details. A few days later, my headers were done and on the truck headed my way. When they arrived, I found that the flange needed to be modified to accommodate the raised plug position. They paid to ship the headers back and two days after they received them, they were headed back to me. The design is a lot different than either of the previous headers I described. They are a cross between the two. I opted for the double collector option to provide a place to install my O2 sensor and get a reading of the entire right-bank vs. one tube or installing in the side pipe collector. I opted for bare stainless to save a bit on the price, which was significantly more than the other two manufacturers.

So, for those looking for options, I've just described three. My advice is to be very clear when ordering that you have the newer Blueprint high-performance heads and you will get a product that fits.

I hope this helps,
Dave