New here and looking for advice with my setup.

leave it the way it is if its stock. That 68 manual cam is sought after by many why change it... basically tune it up see if it needs the parts you want to replace.
not all 68 340 manual trans cars came with the better manual trans cam, they stopped putting them in mid year. the hemi grind camshaft is a perfect fit for a stock motor. 71 stock intake or airgap manifold with a thermoquad and eletronic ignition would just top it off.