OS Giken Releases L Series Head

by Michael Satterfield

In the early 1960s, Osamu Okazaki wanted to build a true high-performance Japanese race car to compete against the sports cars from Europe that were dominating the sport at the time. Like many hot rodders before him, he started working in his garage, figured out how things worked, and designed improvements to increase performance.

A self-educated man, he originally began working on motorcycles and later cars. Mr. Okazaki founded his company, OS Giken, in the early 1970s with strength, durability, and the pursuit of high performance in mind. He only wanted to put his name on the best products and one of his most sought after creations were the TC16-MA2 and TC24-B1 twin-cam heads for the Datsun L-series engine.

The head was designed in 1974 and successfully campaigned on the international rally and circuit racing scene; if you had one on the streets of Japan your car was virtually untouchable. Producing 230+hp naturally aspirated out of a 4-cylinder engine.  The 6-cylinder version (TC24-B1) followed shortly thereafter, with a specific target of outperforming the fastest production car of the time, the Porsche 930 turbo. Featuring twin cams, pent-roof combustion chambers, and 24-valves, producing nearly 320+hp the head effectively doubled the horsepower of the L series engine. Collectors and vintage racers have long prized original OS Giken heads, fewer than ten of some models were even known to still be in existence.

So image my surprise when I saw a 240Z Motor topped with an OS Giken head at the 2013 SEMA show. The engine is pure artwork and while we would love to pick up one for our project 240Z, however, the price is astronomical. The representative said that the head, timing gears, cams, valve cover and intake manifolds will set you back a staggering $32,000 USD, that price does not include the carbs, short block or exhaust header, or the super cool carbon fiber velocity stacks. While we love the idea of picking up a OS Giken head from the speed shop putting a $32,000 head into a car we just paid $1,200 for does not seem like it would be a wise investment. According to the guys at the SEMA show, they have already sold 8 heads on backorder and will be shipping in early 2014. For more visit osgiken.net.


  1. Please allow my hotlinking of this article to my Facebook blog, "Looking Back Racing," if that can be accomplished. /"areopagitica"

  2. The head is still not available, the TC24 just talked to OS on Thursday. I doubt they will get much action if the price stays at $32,000, can do an SR swap in 510 for a fraction of that not to mention an LS into a Z car, not exactly the same thing, but tons of HP and much more than the TC can ever offer. They did not have an update on the TC-16 but maybe next year. Hopefully by increasing production #s they can get the price down to a more affordable number. The person I talked to also said that at this point the set-up was going to be offered as a full long block. I would prefer to be given the option along with a head that can use the standard L-Series chain system. Les Collins racing offers a system that allows the adaptation of the KA 16v to an L-Series with several different options offered to the purchaser and produces 270hp on the dyno.

  3. This Edelbrock 4.0 new Aluminum Performer cylinder head is a bolt-on performance upgrade for 1987-2006 Jeeps with 4.0L inline six cylinder engine.

  4. This a new Aluminum Jeep Performer Cylinder Head is a bolt-on performance upgrade for 1987-2006 Jeeps with 4.0L inline six cylinder engine. <a

  5. Thank you for sharing such useful and informative article. Awesome article on blog commenting, keep the good work. read more on Edelbrock 4.0 jeep cylinder head