Welcome James:
I second what Bill said about bringing the $ for the rebuild.
I too have a '76 Targa with 164,xxx and with a rebuilt (many many miles ago) 2.7. One of the previous owners rebuilt the 2.7. Smokes a little (like they all do on start up) but runs well enough to put on the track occasionally. If I were you, I'd sell the 2.7 to a 914 guy and buy a recently rebuilt 3.0 or used 3.2 before rebuilding my 2.7 (probably same $ in the end). If you plan on keeping the car for a long time I think you'll get more out of the added hp / torque.
Now... that is not to say that there is anything wrong with the ground-pounding, stump-pulling 165 hp I currently have but, somethimes more is better.
Jase