B.E. presents: Legendary Tuning Lore - The OS Giken TC24-B1

Designed by Osamu Okazaki in 1976, the TC24 was a twin-cam, 24-valve cylinder head that bolted on to the (originally SOHC) L28 engine in the 240z and Skyline. The TC24 actually originated from the TC16, a twin-cam head for the four-cylinder L-series engines found in Datsun Bluebird 510s. 

With a built bottom-end and triple carburetors as specified by OS Giken, a TC24-equipped L28 would develop an incredible 320hp @ 7400rpm (9000rpm redline), up from the stock 150hp. Essentially, this aftermarket, bolt-on head allowed the Datsun enthusiasts of the 70’s to turn their stock, torque-focused L28s into full race engines.

This incredible undertaking cost Okazaki-san 20 million yen in 1976, which equates to nearly $700,000 USD, after adjusting for inflation. The TC24 heads sold for $12,000 each in 1976, so they are incredibly rare.

Want to see and hear this incredible head running? Office Tomitaku has a TC24-equipped S30Z, and an awesome video to go with it. Watch it HERE.

As for the future of the TC24, OS Giken has announced that they will be casting more of them soon, at a cost of around $40,000 each. OS Giken is also planning to sell a 3.2 liter crate motor complete with IRTBs and a header for an insane $90,000. It will produce 400HP at 11,000 RPM.




New「TC24-B1Z」Test by OS GIKEN



L16 / Datsun 1600 x OS Giken TC12 Dual cam head.

SUPER rare. 


Hands down my favorite Z-car ever built by anyone. 

Office Tomitaku S30 Nissan Fairlady Z. Many people mistake it for a Nissan Fairlady Z432, which came with a 2.0L I-6 DOHC, but this isn’t one of those storied cars. It’s equipped with a Nissan I-6 with an ultra rare OS GIKEN TC24-B1 DOHC cylinder head, triple Mikuni carburetors, and custom stainless steel header. This head is built for racing! See the water manifold just above the header? It’s an incredible piece of machinery.

My favorite part of it, though, is the radiator. It’s an original brass radiator. Most people would be in horror of such an antiquated piece of equipment in such a beautiful car, but I think it adds a final touch of nostalgia and character to this car. 

More pictures here. Give us a follow, mate.