I always heard about the 1000 mile rule and followed it.

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How long do you run break-in oil in a rebuilt engine?
In general, run the engine under light-to-moderate loads for about 500 miles. Again, that duration is a rule of thumb, but break in shouldn't exceed 1,000 miles.


You are almost there so changing it won't hurt.

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I checked the PCV valve and it's good.

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yes, pcv valve is connected to a port on the carb.

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Might also do a kwik blow by check before pulling the intake.


So where is the pvc connected to after the EFI And you said the pvc valve works but what about blow by? Take off the pvc valve and see how much "blow by" comes out after you are at operating temp. If it's excessive that's what is blowing oil into the intake.