We were blown away last weekend when we showed up at Accufab in Ontario, California, with our buddy Larry Larson. We expected the “no camera policy” to be in full effect, but it was just the opposite. We were invited in with open arms, and got to check out all the manufacturing and race operations, including the engine building room. In fact, Accufab owner an racer John Mihovetz himself gave us the penny tour and explained some of the details that go into building his 2,500-horsepower Mod Motors. Accufab is arguably the leading manufacturer of throttle bodies in the industry, and it was bitchin to see all the billet that goes into making one of their killer pieces.
When we got to the shop, John led us through the offices and then into the manufacturing facility which takes up half of the building. The race shop and product assembly takes place in the other half. John jokingly said that the manufacturing side made the money, and the racing side spent it. And considering he recently crashed the familiar Accufab Cougar and had to replace it with a Larson Race Cars built Cobra Jet Mustang, he wasn’t really kidding. According to John, Accufab builds thousands of throttle bodies each year, and other than polishing and anodizing, the manufacturing all happens at the Ontario, California, facility. Throttle bodies are taken through many machining steps, in various high-dollar machines, before being sent off for polish or anodizing. When they return, they are checked and then engraved before being washed, assembled, and packaged. Every Accufab throttle body is assembled in one room by the same guys every day. Design, Research and Development, and Testing all happen in the same building. You wouldn’t believe the number of throttle bodies, clamps, throttle blades, and parts that are various stages of assembly. It’s bitchin’.
After checking out all the throttle bodies and talking to John about a new throttle body “system” he is currently developing for the big-inch nitrous racers, we headed on over to the race shop. The first thing we noticed was the ’66 Mustang Fastback sitting under a cover, on top of the assembly room. Yes, every Accufab throttle body is assembled underneath a ’66 Mustang. The next thing we noticed was the Larson Race Cars Ford Mustang Cobra Jet up on stands with the front end and doors off. John later explained that they were cleaning up parts of the car that they had “temporarily configured” during a last minute thrash in preparation for the Street Car Super Nationals in Las Vegas in November. This car had belonged to BangShift.com sponsor Aeromotive, who is now having a new Cobra Jet Mustang built at Larson Race Cars. With this car available, and one of the only in the country setup to run the twin-turbo Mod Motor Mihovetz is famous for, it was the natural choice.
Speaking of twin-turbo Mod Motors. Wow, was John an open book. We almost felt bad asking questions, so we stopped. What we did find out was that John’s team builds each and every engine in house, including balancing, porting, valve seats, and assembly. They are currently working with Serdi to design a new valve seat cutter that will result in less hand porting, more flow, and consistency. But arguably the most interesting thing we found out about Accufab’s race engines was the fact that they balance their camshafts. Yes, you read that right. And after looking at them, it makes sense. The camshafts in these Mod Motors are provided by Comp, and due to more cam lobes being on one side than the other, they are inherintly out of balance. 50 grams out of balance. Enough that, with all four camshafts spinning inside the 9,000-rpm engine, John could feel a vibration in the last couple hundred feet of a drag strip pass. Balancing the cam require a precise touch, and patience, but the results have been worth 4 mph in the quarter.