That appears to be a DLA 64 twin. I don't believe DLE ever made an inline twin. Any muffler made for a DLE, DLA, EME or several other Chinese engines in that size range would fit the exhaust port on this engine but I'm not sure two of them would fit next to each other on the inline twin configuration. Does DLA still make mufflers for this engine? If not, maybe custom made mufflers from a company line Jtec or Bisson would work for your scale application. If you can tolerate a bit more nose weight, it is easy to fabricate a custom muffler from steel sheet, cut and welded to shape.