I'm trying to find a SAR2 to make an AIMS74ish clone. I found one for sale, price seems in line with recent sales I've seen on EE and on otherforums, plus it comes with some nice extras (mags, push button stock). Here's my problem, a previous owner had the barrel threaded to what I believe is 1/2x28 threads (bit of a guess but it has an A2 style flash hider on it. I understand this would be covered by a threaded Romanian 22mm fsb if converted but, I'm worried about a gap between the barrel threads and the portion of the fsb covering them. Thoughts?

No, it won't be a problem. Might catch some carbon blowback from muzzle device, but that'll just fill the gap up over time.

I have a SAR-1 with a Bulgarian 24mm FSB fitted on due to an overzealous turning of the factory threads.  It has that gap, but it really isn’t a huge deal.

If you plan to shoot corrosive surplus, it’ll need a little more attention when cleaning since it’ll let stuff collect easier.  You could probably find someone to make a 1/2x28 sleeve that would fit over the threads and under the 22mm FSB.  I’d bet Morgan Richey, our resident barrel whisperer for threading, could do something like that.

That said, you might find it cheaper to buy one of the AIMS-74 clones from Atlantic Firearms. I had my SAR-2 converted back a long time ago, and between the parts and labor, it wasn’t an inexpensive project.  The kits are available now, but still fairly expensive.  I bought the Atlantic as a compliment to my SAR-2, and its a nice rifle.  Couldn’t build it for the price they’re selling for.

I thought about going the Atlantic route (still might, looks like a very nice rifle). I really like the idea of a Romanian factory receiver and barrel as well.

If you don't mind spending some money and having the conversion done right, go with the SAR 2, if your budget minded go the Atlantic route.

Follow up thought, any opinions on a SAR2 vs a ROMAKII for an AIMS clone project?

RomakII might have better finish and might have the upturned handle carrier already, depending on the timeframe it was imported. The IIs were imported earlier than the SAR-2s.  Otherwise, they’re going to be pretty close to the same.

Condition and price will probably be the major differentiating factors.