is there anyone who could make a sar-1 into a ak104?
will a russain plastic folding stock work on the sar-1 rifle?
thanks for the info.

There are some key base differences between the SAR-1 and the AK104. The gas block would have to be replaced with a 90 degree, possibly requiring filling in the old gas port and drilling another, the barrel shortened, and a new FSB installed- which might have to be custom done because of possible differences in the outside barrel diameter between Romanian and Russian rifles. Another difference would be the finish. The Romanian rifles seem to use a combination of parerizing and bluing for finish. The russians use a baked-on paint which looks quite different. There are also some other differences, depending on how closely you want the details to match.

The folding plastic stock would require changes to the receiver, holes cut, etc. and possibly a new rear trunnion.

As you can see, the changes would be quite extensive if you wanted to get it very authentic.

Now, if you just want to shorten the barrel, have an AKSU-type brake installed, and black polymer furniture, you'd be looking at a much less expensive project.

Decide what you really want, how much you're willing to spend, and shop around with the various smiths. If you don't already have the SAR-1, it might be cheaper just to buy an already made AK-104 clone from AKUSA.