I have a D-28, 1976. The guitar sounds pretty good, balanced, yet not powerful at all. Any thoughts on how to best get more volume? Is it feasible to pull the top and change bracing or top or would that be a crap shoot at best.
I like the guitar, plays great, yet I also have a 000-2h which of course sounds wonderful and is as powerful and balance of a guitar as I've ever owned.

Email this guy http://www.bryankimsey.com/ and see what he thinks.

Don,
As Allen says, you'll get a lot of very good info from Brian and his web site.
I took another approach with my 1970 D-28 and 1977 HD-28, but the most impressive result was with the plain D-28.
As I am the original owner, I did not want to pull the popsicle brace, scallop the braces, and replace the rosewood bridge plate - any of which would invalidate my warranty.

I had the following done:
Warranty - neck reset, pickguard crack repaired, pickguard replaced (I bought the Greven dark), saddle slot filled and moved to the correct place, and fretboard trued.
Work I paid for - stainless steel frets, Waverly tuners, bone nut, saddle, and bridge pins.
The D-28 is absolutely stunning! It is louder, more powerful, but - even better - sweeter. As I had similar work done to the HD, the HD is still louder, but doesn't have the quality of tone the D-28 has. It is my best guitar and better than any new one I have played.
John

Thanks to both for emails...great ideas in each. I guess I should've realized earlier that there have to be others who bought the mid 70's Martins and were not satisfied...and did something about it.
Appreciate it.