It's cylinders are "siamesed" meaning that instead of coolant flowing between all the cylinders as on earlier models, they are connected between 1-2, 3-4, 5-6 with cast webbing for more rigidity. In addition, all Datsun did to make the F54 a turbo motor was to replace the flattop pistons with dished ones ( to lower compression), and add a turbo head with better exhaust ports and a goofy distributor.