The more minor difference between the old triangle on the right and the newer triangle on the left is the small metal bridges in the rear forks of the newer triangle. These I easily removed with a junior hacksaw. The more major difference is the new frame only has one braze-on for a gear pulley block (these slide into the braze-on and are secured with a machine screw that has a circular head where the Bowden cable enters the block; I used small locking pliers to remove this easily). I very carefully removed the required additional braze-on from the old frame using a rotary tool (a Dremel). Since I only had one chance at doing this right, I erred on cutting into the frame rather than into the braze-on, and tidied up the cut edge with a hand file.
