How can I figure out my engine specification?

Hi guys.

I'm not good at english. sorry :sweatdrop



My rx-8 is 2004 automatic but, engine was changed by previous owner.



Just I know is

1) Engine Number(6 Digit)

2) Engine's year(I heard that 2005 later model)

3) Undergo some modification to previous engine parts(for mount 2005 engine. I heard that modification to the intake parts)



Nothing problem with my car. runs good.

But I want to know CURRENT engine specification(4-port or 6-port, correct engine's year)



Is it possible to know engine specification with Engine Number? (No Mazda dealer in my country)