The PMB 914-6/GT

The PMB GT

Twenty years ago in 2005, The owner and founder Eric Shea, was pondering the build of an ultimate 914-6; an accurate replica of the 914-6/GT race car but built for the streets. He didn't know it at the time, but his personal project car was about to become one of the main building blocks of the business we all know and love today, PMB Performance.

Beginning With The End in Mind

Eric’s first Porsche was a 914.  Sitting forlorn on a used car lot, this Adriatic Blue 1.7 was about to get a transformation.  A complete 916 body kit and, the flavor of the 80’s, “Guards Red” paint completed the scene.

  He then moved on to various 911’s with a 66 and a 71 that he still owns today.  It wasn’t long before his interests came back to his mid-engine love, the 914. He found a 1970 one owner 914-6 that became available and the journey continued.  He restored the factory 914-6 and last seen it was at the Porsche Museum at Silverstone.  It was such a nice car that he wouldn’t “dare” do the things he truly wanted to this car so yet another 914 project car was purchased. The PMB GT started life as a Northern California chrome yellow 1974 914-4 tub. By this time, Eric had narrowed down his idea of the ultimate 914 and the time was right to bring this vision into reality.

The first step with any ground-up restoration is to strip the tub. Luckily, it was a completely straight and (mostly) rust free example, meaning minimal repair work was required. The car was stripped down to the bare tub, and the meticulous GT process began from there. 

Next it was time for the metal work. The left front and rear had minimal accident damage from tapping, correcting and tapping a guard rail again

The fenders and the damaged metal were all cut, and a set of original Porsche M471 flares were procured and welded to the body. Luckily the original flares came with enough metal to completely repair the previous accident damage.  The chassis was stiffened using the factory GT stiffening kit to help with the 914's "flexi flyer" nature. 

Adding flares to the body and widening the track width allows for extra tire contact patches that can cause unique stress to the rear longitudinal section and suspension mounts. To counteract this stress, the decision was made to replicate the race department’s GT Inner Ear Stiffening Kit. This is the same kit we sell today.

On top of the widening and stiffening, a few other crucial cuts to the body were made. The front apron received the factory oil cooler cutout and subsequent front suspension bracing. A large (factory size) oil cooler exit hole was cut in the bottom of the front trunk, as well as GT oil line access holes in the front bulkhead. All required for a properly plumbed GT Oil Cooler. Front mounted oil coolers are essential on any high output air-cooled Porsche motor.

Getting the Ball Rolling

Once the body was all prepped, it was time to turn the tub into a roller. When converting a standard 4 cylinder car into a 914-6 or 6/GT, there's a lot more going on in between the chassis and the road.

Starting at the front, the car was converted to run the front suspension used on the factory GT’s. The Koni Front struts had their spindles raised and the process converted the car to the ever important 5 lug system. This allows for much better caliper and rotor options. We opted for the Koni suspension as it's authentic to the car's racing heritage with factory GTs running that exact setup.  The car also received a rare one-year only 18mm 1974 930 front sway bar and RSR arms with adjustable drop links.

Once the front end was sorted, it was time to get the rear suspension together. For shocks, we sourced a set of super rare factory 3-way adjustable Koni shocks and springs. Once again, these shocks are the same equipment found on the factory GT Race cars. Completing the rear suspension is a set of PMB strengthened trailing arms and 5 lug rear wheel hubs.

The GT, sitting on it's new Koni Suspension with 5 Lug hubs and iconic Fuchs

Both ends of the suspension are held in place with standard rubber bushings and stock torsion bars. While that may seem strange, it follows Eric’s philosophy of how to bush a road going vehicle.  The #40 Le Mans winning GT had… rubber bushings.  So, when you're building a road car, it's important to keep the use case of the car in mind. You can build a car with the biggest and stiffest suspension around, but most of the time you won't see the benefit and may even experience downsides. It's important to build the right car for the job and not just the most extreme one.  Here’s where the Pareto Principle (80/20 Rule) applies. 80% street? Rubber bushings.  80% track? Harder (Poly-Bronze type) bushings.

Stopping Power and the Origin of PMB Performance

Once the car rolls, it obviously needs to stop. When Eric was building this car back in 2005, it was the dark age of braking support for air cooled Porsches. All of the "Big Box" brake suppliers at the time were putting out the wrong calipers for the year, wrong pistons, wrong coatings, just a general nightmare. The 914, with its complex integrated handbrake arm, had it the worst.

Obviously, this wouldn't do for the 914-6/GT dream car, so he took it upon himself to learn the required info to rebuild these calipers correctly. In his search, he learned that the 914 and 914-6/GT share a rear caliper with the Ferrari 308. This led him to a small online article for rebuilding these calipers (written back in 2003!)

Using these newfound skills, and some fancy zinc plating from the local plating company he befriended while restoring his 911, Eric put together the very first ever set of PMB Calipers. People on 914World were impressed with the quality and attention to detail of the build. So impressed in fact, that when Eric posted his first set of calipers for sale online, they sold in under 15 minutes! Once the first set sold, PMB Performance was up and running. Orders came flooding in. It all started as a side shuffle in the garage to help pay for rare and pricey GT parts.

The first ever set of PMB 914-6/GT Calipers

As for the calipers that made their way onto the car, up front Eric's car features a set of Versuch 908 conversion calipers based on the Early 911S caliper forging. This was heralded to be on of the first 908 prototypes with a 910 style pad clip and from the forging that would eventually become the S-Caliper once the 911S went long wheelbase in 1969. The original caliper came from a factory GT collection up in Canada so it seemed fitting to install them on the GT. These forged aluminum calipers feature a larger brake pad as well as a 48mm piston, and support a vented 5 lug 20mm thick 911 brake rotor.

Eric's 908 "Versuch" Calipers on his Factory Koni Struts with RSR Sway Bar Links

The rear of the car uses a genuine 914-6/GT caliper. The GT Caliper is the only way to run a vented rear rotor while also retaining the factory handbrake functionality and correct bias with a 911 front end. Even back in 2011 when Eric was originally looking to do this upgrade, it was difficult. The 914-6 Calipers were few and far between and expensive, rotors did not exist, the spacers and extended hardware were poorly documented and difficult to find, and the pad hardware was expensive and not quite right. Luckily since then, PMB Performance has pioneered a true bolt on conversion for the GT Rear.

Heart and Soul

Now that we have a car that can roll and stop, it's time for horsepower instead of manpower. Jeff Hines came to the rescue crafting a period correct 2.5 liter twin plug powerplant for the 914. The factory 914-6 is a 2.0L magnesium case motor with Weber carburetors. That motor is a lot of things, but anyone that's driven one will tell you one of those things isn't fast. When the Porsche race division was preparing the 914 for Le Mans, their solution was to put a 906 twin plug motor into the car. The 906's motor was a 2.0 purposely built to meet the rules for 2.0L class racing.  If Porsche was anything, they were rather modest with their hp ratings.  Their official publications state 906 had 210hp on paper.  Later, as the class rules changed, most of these 2.0 powerplants were bumped to the new 2.5 displacement.  The PMB GT sports aggressively jetted triple throat Weber 40-IDA3C carburetors.  The factory 906 motors used the 46-IDA’s but here at 4300’ in altitude the 40’s do just fine. The big Mod-906 cams, and twin plug ignition turn the beast into a fire breathing monster. Jeff built his motor to these specifications and the result is a high revving extremely peaky NA powerband that has to be driven to be believed.

The car delivers its newfound power through a flipped R&P on a "Type 916" Transmission, which is a modified 1970 and 71 911 gearbox set up to run in the mid engine layout of the 914-6. This was the interim transmission that sat between the 901 and the 915 transmission for the 911 models. This trans runs larger 108mm CV joints on custom length free floating axles that are built to handle the higher torque of the aggressive motor.

Exhaust is handled through a set of stainless steel heat exchangers running into a factory 914-6/GT rally muffler. Porsche's rally muffler was a 1970s motorsport requirement that stated homologated race cars were required to run some kind of muffler for running races in urban areas. Porsche's solution: run two straight pipes through a big empty muffler. It's exactly as loud and intense as you'd expect from that description. Gotta love that 70s motorsport rule bending!

Finishing touches and little details

Eric's car took until 2013 to complete. 7 long years of collecting rare and hard to find parts, and building up the required esoteric knowledge and skills, and two solid years of actual build time. The car was re-finished in its original chrome yellow, with RSR style frosted anodized Fuchs, and a simple black GT interior.

Eric didn't stop at just flares and wheels when it came to styling the car after a true 914-6/GT. The car features a unique Rally Wolfsburg 1971 rear plate riveted into the trunk, a pit light on the roof, and a unique gauge cluster layout. The car also features a GT style hood, with a cutout for a fuel filler, hood pins, and a GT hood prop.

Eric's GT and PMB Performance

By the time Eric's GT was complete, PMB Performance had grown into a full-time commitment. The car received a 10-page write-up in Porsche Panorama Magazine and a coveted feature on Jay Leno’s Garage.  Soon, the calls began coming in for Eric to build and restore other people’s cars. The PMB Coachwerks division was born. Now with our Coachwerks division, a full-time Brakewerks division, and the launch of a new website, PMB is busier than ever. 20 years after the first set of PMB calipers sold on 914world, we've moved into a larger building, continue to crank out the cars of people’s dreams, restored tens of thousands of sets of calipers, and our website has grown to an astronomical number air cooled Porsche and VW parts. At the center of it all, Eric's 914-6 GT stands as the car that started the business, known for its regular appearances at trade shows, Red Rocks Classic, and other events around the country.

If you’re ever in the Salt Lake City metropolitan area, please stop by and say hello.  We’ll be happy to give you a tour and talk vintage Porsches until the sun goes down!