Distributor Plug Help!

Hi,

I've upgraded by early 74 260z from the 2.6L to a 2.8L. Part of the upgrade was to also switch from an auto to manual trans.

I bought a 2.8L from a guy with an existing distributor. Unfortunately it has a "rectangular" plug while I have the round plug (three wire).

The new distributor has two black and one white wires. My old plug off the harness is Green Red, Green White and Yellow. I've already determined that the yellow wire can go (compared the auto vs manual wiring diagrams).

Not really sure how to mate the harness wires to the distributor.

Any suggestions would be welcome.

Thanks