This is installing a 3FE exhaust on a 2F but same principle 3FE exhaust on 2F head - https://forum.ih8mud.com/threads/3fe-exhaust-on-2f-head.955034/. Scroll through the thread and there are a few photos. We're going to be doing something similar for a 3FE in the next few weeks using a pair of...
Take it to a muffler shop and have the down pipes cut off above the under-the-framerail- pipe. Merge the two short sections into one and run the exhaust on out the back.