Hello , i just found out about the ak 104 , i am in love with it and i would like your knowledge about some questions i have.

1) I am considering to change the barrel on a regular akm and put a 12.5 inch barrel on it (make it 104 ish clone gun) and i was wondering about the original ak 104 gas port/hole size.

2) Also i need to put a combo gas block on it and i can readily find the Jmac customs adjustable gas block , what is your experience with it? (any problems? I am looking for high quality parts that wont blow or crack )

3) Regarding the barrel length , will there be any reliability issues when the barrel end is so close to the gas port?

4) I read that any short barreled ak needs a booster in order to be reliable , is that true and to what extent? Personally i dont plan to use the regular booster but a suppressor on which i read that it increases the backpressure and basically works like a booster. Any ak 7.62x39 suppressor will make the gun work reliably?

If you think i am forgetting something that i should know dont hesitate to write it below.

Thank you!

1) It's slightly smaller than a standard AKM gas port and done at 90 degrees vs "45" degrees.

2) The JMAC block is a quality casting. You have other options, like the DAG-13 or the Occam Defense adjustable combo block.

3) No.

4) No, a properly built rifle should not need a booster to operate. They aid in reliability when the rifle is extremely dirty or in a very cold environment.

Do you know the exact numbers for the gas port? Thanks

I have made my own 105 and did nothing to the gas port.

For my 104 I simply bought a PSA GF5 104, probably the best decision I could have made.

I will say this, the 102/104/105 is the best handiest AK model ever made, and yes that's my opinion. I've had just about 1 of everything that was ever imported into the states or that we could get parts for.

Did somebody say short AKs?  Thats my jam, son.
AK 102, 104, 105 and the clones like arsenal 106-CR and 107CR.  PSA's first one in that length was the AK-E (and AKE-S).  Then their 102/104/105 line.
Romanian PM md. 90 is the military version of the 12" draco pistol thats imported to the US.
The Israeli Galil SAR is a 13" version.

For an AKM here in the US, some of them have 24mm threaded gas blocks and some of them have the barrel threaded.
PSA sells the FN CHF/CL barrel.  That is what is used on the AKE and their 103, along with a combo gas block that is not threaded.  I chopped my barrel and threaded it 1/2-28.

You do want to pick the correct gas block and gas port for each other.  Some are straight, some are 45 degrees.  
I dont know about the jmac gas block.  They are still relatively new and only really get used on overpriced boutique builds by US builders for people to show off on reddit.  You're not gonna find any long term or high round count review of them.  K-VAR sometimes has the gas blocks for sale.  And PSA sells a couple different versions.  Looks like the AK-E one is in stock but their threaded 104/105 one is not.

None of them I've shot need a booster.  Thats something for the 3rd world shitholes where the gun has seen 20k rounds of full auto and hasn't been cleaned.
The ones we see here in the US will launch empty cases 30ft with no booster.

With the amount of different options for complete guns, I would say just buy one that already has the barrel and gas block you want.  Only bother trying to convert an existing AKM if you're bored and want a project.

I've got a Draco AK (12.25" barrel) I SBR'd, no booster needed.

Important to make the distinction now that its the Romanian draco you want.  Century is pulling a bait-n-switch with a US made turd they're also calling a draco.

If you're 100% on the build route you can also find a classic styled combo block on PSAs site.

PSA 104/105 combo block

True.  Mine is Romanian.

Yea, I noticed that.

Go Romanian, always. Till the US manufacturing can duplicate Warsaw pact level of AK manufacturing.

Definitely avoid the Century made ones, I believe they are the RAS or BFT line.  They are not dracos except in name.  Century imports gems and manufactures trash.  Every now and then, they pick a subcontractor that actually makes a decent gun (HK 5.56 clones, Sterling 9mm).  But for the most part, it's safe to avoid any Century made guns and stick only to their imports.

I picked up a couple of 7.62x39mm Romanian Dracos (12" & 8") during the 'brace ban' for a really good price.  I think people lost interest as you couldn't throw a brace on them.  Now that braces are 'legal' again, I need to stick a brace on them.  I tried to trade one for a Yugo in 5.56, but didn't get anyone interested (and I was going to put cash in on my end).  I even got a 9mm Draco really cheap that I'm either going to put in a STInc. bullpup stock or get the new Bizon style drum conversion for it.

I think I'm going to get a CNC Warrior brace for my Draco.  Those look like they are incredible stable and I have only read good things about it.

STInc Bizon info page

@ihon
The 9mm draco is also a bait-n-switch.  Its made in cugir romania, but by a completely separate factory that made military firearms and the real draco everybody knows and loves.

NAC-9, PAC-9, and draco 9 are all coming from Nova Modul.  https://novamodul.com/  They are a very new factory who, up until recently, didn't even have a gas operated gun in their catalog.

Yes, I actually discovered that after I bought it.  It has made in Romanian stamped on it.  It definitely isn't up to military standards as there is a plastic spacer.  They capitalized on the the Romanian military guns and sneaked this one in on me.

I got it because it was cheap ($400ish) and wanted to try a STInc bullpup kit.  Now that they have a Bizon kit, that's what I'll probably do with it.