[Tron]

Go to your hardware or auto parts store and pick up a "Torch tip file". They are only a few bucks or so. Make sure the tip file is long enough to get in there...some tip files are too short.

Tron.

 

[Texas Ton]

I'm not familiar with a 390, but on everything else I use a pin vise and a drill bit the same size of the ports. A pin vise is easily found, any welding supply store has them for about $6 and they come with bits, but you may have to buy another the exact size needed. If it's like a 391, this will work.

 

[BigM-Perazzi]

u access the holes thru the gas cylinder using what joe recommends. I used to use extended length drills but there tough 2 find.jim