I believe I heard Henry at prime sports sub out others barrel. Prob can do it to the ak47. Headspace gauges will be needed though. Since the process requires a press, unlike the traditional ar15. I'm sure you know that.
If your asking tpi, I'd go with 5/8-24 since most are bored out to .360" or higher, and much more options but that's my pov. Find a muzzle brake you like with proper inner dimensions then do your barrel. Good people can time the thread perfectly so it's flushed fit and nice as long as they have the muzzle device on hand to do their measurements
I'm not looking to replace the barrel, at least if I don't have to. And I'm pretty much a rookie when it comes to AKs to be honest. Much more of an AR guy, who also is interested in AKs as well.
From what I've been told from shooter friends that are more experienced with AKs than me, there's enough of a section/length of barrel that extends beyond the front sight tower to thread for a muzzle device. Just a matter of finding someone to do it. I've seen all sorts of DIY videos and tools, but that's not for me. I really just enjoy shooting guns as opposed to tinkering with them.
I've been doing some research on muzzle devices and if this gun is a keeper as a project gun and shooter, then I'll likely discuss what device choices I have with the person who would help with the threading. Not looking for anything in particular, just don't think I want just a plain muzzle, at least my current vision for this gun.