Tapping water pump for AN fittings

[Motown 454]

Hi I have my accessories on my motor already and I am thinking of tapping the Heater ports on the water pump for AN fittings. If I use grease on the tap to catch the chips will I be OK doing it on the motor?
If I don't do it on the motor i will have to figure a different way to connect the hoses.

I need opinions please.

Thanks

[raustinss]

It helps not a perfect way...if possible remove it and try to tap with grease and upside down