Ah, so it an L20B that's been bored & stroked. Not an LZ hybrid (Z-series block with L-series head, or L-series block with Z-series head).

NAPS-Z is what some people call the Z-series engines, because some of the valve covers say "NAPS-Z". But technically NAPS-Z refers to the emission control system. There is also a NAPS-A.

Does NAPS stand for northern american piece of sxxx lol

NAPS is a Japan design. Used in Japan first then later in other countries.

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The engine definitely an L20B with a modified z24 crank and z24 pistons, giving it a 96mm stroke and 89mm bore. The head is a u67 which has been ported with oversized valves and the chambers been relieved. It's compression ratio is 10.5-1. Running a 74 high lift cam, advanced to bring on the power a bit sooner.

Nice grunter

Nice job on the tune mate would be a heap on fun to drive now. Randys dyno does read low my car made 107rwkw on there a long time ago then at the ozdat dyno day made 128 on the same boost

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Ha, I assume they're pulling you over to check your log book? I hear they're quite strict on those recently. I hope you had it all filled out correctly!

That area looks familiar, are you Eastern suburbs Melbourne?