I want to purchase a 14.5" barrel for a Frankenstein AK build. The barrel in particular does not have the gas port drilled. I also want to use the Venom Tactical AK47 /AK74 Gas Block. I assume this will be a 90 degree port opening. Where do I go to find the info on what size gas port hole (#42 drill?) and the exact location of the port on the barrel? Is the location based upon first populating the barrel and determining the right position of the gas block? Since I am pinning the barrel, it needs to be perfect out of the box. I am an AK builder newbie but excited to learn all the ins and outs.

http://armsofamerica.com/amd-65usmadebarrel125nitridelined-1.aspx

Yes, you determine the distance based off of the entire population of the barrel, since depending on your headspace the barrel may be a little more pressed in/out than someone else's build.

The same barrel is here:

Barrel

As well as the appropriate drill bit:

Drill bit

You could probably get away with a smaller drill bit, but that should guarantee it runs. Luckily, since you're going to the Venom block you could always just loosen the screws and move it out of the way to open up the port if needed, but I doubt you will. I used the linked bit for my 8" AKMSU build and it runs perfectly.

ETA: The same bit is available from AoA (since he gets them from AKB)

AoA drill bit

Thanks, AEnemaBay!
I appreciate the additional links......I'm surprised my google search couldn't pick up that product page. I am gathering parts and tools now. Curtis at AK-builder seems to run a stellar ecommerce business as I am impressed by my purchase last week.