Mac AV1838 - Carburetor replacement substitute?

[B.C.]

Have a McCulloch MS1838AV, I spent quite a bit of time on it tearing it down and cleaning up good. Had it running pretty decent for a while but I think it really needs a new carburetor. The H & L screws were both out like a good 4 turns. I did put a genuine walbro kit in it but it just doesn't seem to tune well. Piston looks fine. It has a WT-349 in it. Read somewhere that the WT-774-1 superseded it. Can't seem to find either carburetor anywhere new for a reasonable price. Don't want to pay 50+ bucks for a darn carb. I really like the saw though and I'd love to have it running nice again. I paid 20+ for a darn spike for it too and I put a new oiler and clutch drum on it. Wondering if any other carburetors that might be more readily available would swap in? I do have a number of potential donor saws including a bunch of poulans also with 18" bars and a few old homelites, a 240 and a 300 if I would be so lucky that one of those would work but probably not that lucky. If anyone knows of another option or one of the 349 or 7741 for cheaper that would be awesome.