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The Z24i from the 86.5 or 87 will be an easy install mechanically it's all about the same. But you'll need the entire wire harness and ECU from the Hardbody because it is throttle body EFI. You'll also need a EFI fuel pump to go in between your normal fuel pump and the engine. It will take a lot of splitting and splicing to the wire harness to pull out what you need for just the engine a leave everything else alone. I'm not sure how this will all work with CARB but since it's a newer engine as long as you keep all the emission equipment and CAT from the 86-87, it should be OK. The sticking point may be the fuel pump. You may need the in tank fuel pump from the Hardbody to be CARB compliant, and I'm not sure that will mount into a 720 tank although they are very similar.