1986 300 sdl injector discoloration

Kent i removed all six injectors from my "86" sdl to check and clean. 1,2,3,and 4 look okay. They have a little carbon and they are still shiney on the bottom.5 and 6 also have carbon but a blueish hew where the others are shiney. Whats up with that? Looks like they got hot Why?

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