So I have done the Super duper galley plug kit to my case.
I got to thinking that's not hard..... can I modify my Melling 30mm oil pump to full flow?
So I got my huge 3/8" pipe thread tap and tapped the "out hole"
Steel pipe plug doesn't go all the way in. Probably because the tap gets to the bottom of the hole and hits a lip inside.

How far do I need to go should I just get the plug in there and then grind off the excess?

This is on a spare "junk pump" so it is practice and experimenting.

get a flat bottom tap.
You need to start with the normal tap, then switch to the flat bottom to get threads all the way down.
Making a flat bottom tap is easy...grind off the starter threads on a normal tap...grind till you are at the full diamter.
You really need to have both taps for the future though..
Rich

Yea I thought of that. So my plan is to wait for my buddy to come back over. he has a "Mad collection of Snap on stuff" Talk him out of the nice 3/8" tap. and then cut mine off with a cut off wheel grind flat.

Perfect. I tease him all the time about leaving his tools at my house.
Just dedicated a rubber maid box labeled for his tools

The Melling pump is NOT wise to use for full flow. The internal specs of the pump when used with a full flow cover have caused surge problems for us EVERY time I have tried the combo.. You can try it, but you can use a stethoscope on the oil line coming out of the pump and hear the surges... If is tounds like a beating heart- thats not good! (yes not a mechanics stethoscope, but a medical unit)

Sometimes it's bad enough that the oil line will shutter!!

BTW- You can chop the bottom off of a tapered tap and make it into a bottoming tap if needed, bottoming taps are not the easiest to find.

I 100% agree with Jake...do NOT use a smelling pump.
(BTW it's more like 38mm)

Something like 40 bucks gets you the right pump off of Jake.
26mm is good for stock, 30mm for hipo and galley plugged.

Be carefull with making your own NPT tapes. If you bury them too far into the hole, you won't get the plug to fit. Better idea is often to cut the plug down.

I think Matt is onto something. A pipe tap is supposed to be tapered. If you use a bottoming tap, you defeat the purpose. You may never get the pipe seal you are supposed to if you try what you are suggesting.

I don't like cutting the plugs down.
You only need to grind the tip off of a tap. Grind a bit, try it, grind some more. You don't want a huge amount of torque on the plug as it could distort the pump body. Let the locktite do it's work.

Make a "bottoming tap from the 3/8" pipe thread tap. Taper is not affected.
I'm with ya. But since I am probably going to go to a Type 1 30mm full flow pump this is all a mute point.
Last thing I need is screaming down through a sea of cones at 7000 RPM and waste a motor because I tried to cut corners.

Jake thanks for the insight to Melling pump surging thing. I put this very same question on your site. you can kill it if you want.