Carb Synch'ng on a '86 500

I borrowed a buddies mercury stick to synch my carbs a few weeks ago. I broke one of the little brass tubes that threads into the side of one of the four intake manifolds (threads broke off into the little hole) I cant find a replacement brass or copper tube the right diameter at the hardware store to cut threads on, and I can not rethread the length of tube that is left, so I need to replace. Motion Pro sells them.
Do I need the 6mm or 5mm?

Hoping to find out today, so I can place an order, instead of waiting to get home tonight to measure the ones that are left. Thanks

 

The threads are M5. Here's a little tip: a 10-32 thread is almost identical. More than likely the Motion Pro fittings are 10-32 threads (my MP appears to be). Try an Industrial supply place in your area, they should have some 10-32 pneumatic barb fittings that would be perfectly.

 

The size is 5 x .8

 

Actually it's M5x0.8, but that's the standard Metric thread so it can be shown as simply M5. In Metric a designation of 5x0.8 is just a 5mm drilled hole that is 0.8mm deep.

 

True enough, but if someone asks for a screw size they shoud be able to figure out what 5 x .8 is all about.