Cool that is what i was looking for. I am under the assumption that the block is aluminum as well as the heads?
Like was said, iron block and aluminum head. Powertrain-wise the Miata's a bit of a parts bin special. The 1.6 cars used essentially the same engine and rear end as the 323 GTX (turbo, AWD) minus the turbo. This was good in that the engine can take all sorts of abuse but bad for the rear end because it was only designed to take half the power, half the time. You'll see many 200+ RWHP Miata engines running very reliably on the factory internals. Mazda took the same approach with the factory turbo'd Mazdaspeed MX5, in that the block wasn't beefed up for turbo duty.
