!979 Yamaha FG-331

A refret will bring the action down slightly.

You need to check the neck relief first. Use the strings as a straight edge. Press the E strings at the 1st & 14th frets and check the gap at the 7th fret. I like to see 1 to 2 paper thicknesses, about .004/.008". If this is excessively high it will affect the action. This will also tell you if the neck is twisted, you'll get different readings. If this is high you'll need to adjust the truss rod.

During a failed attempt to adjust the truss rod, the truss rod nut buried itself into the neck, instead of the neck curvature changing. At that point I had run out of travel on the threads on the truss rod and couldn't adjust it anymore if I tried. So I made this procedure to eliminate the truss rod from the adjustment, it just holds the neck curvature, yamahavintagefg.boards.net/thread/14/properly-adjust-truss-rod

Once the neck is straight, use a 24" straight edge to project the neck to the bridge. Ideally you want the neck to project to the top of the bridge, up to 1/16" above. More than likely it will project below. Less than 1/16" can possibly be "fixed" by sanding the bottom of the saddle (depending on how much saddle you have left) or sanding wood off the top of the bridge. 1/16" or more will require a neck reset.

I've never done a neck reset on a late 70's FG, but I assume it won't be much different than the procedure I wrote. yamahavintagefg.boards.net/thread/18/vintage-yamaha-neck-reset-procedure If you read this you'll get the idea this isn't an easy thing to do. There's a better chance you will screw up your guitar than successfully complete it. I watched lots of video's, read lots of stuff, and asked luthiers questions. Then I attempted to do one myself. I started on a $30 FG-200. Completed successfully, but I overset the neck slightly, resulting in a .22" high saddle. Some day I'll take it apart again and fix it. Too many other projects.

Have your luthier read my procedure, add some comments, and let me know. I've never been instructed how to do it, just what I've observed online, and I've made changes will some of the ones I've done. I keep learning.

I know no one else that does neck resets on old Yamaha's. As you'll read, the 2 problems are the neck pocket isn't below the 15th fret like most guitars, it's about 1/8" towards the heel. And they used way too much glue, gluing the face of the heel to the sides of the guitar. It's necessary to use a neck jig to press of the neck, along with steam.