I had too do this not long ago on a ld340, i tried the heat and srink method also but only had a propane torch and i think it didn't get hot enough, anyway when i try turning it out it began to crush, i was shitting myself at that point that i may destroy an otherwise good manifold, i then used a air hack saw and made a few cuts parallel with the nipple being careful not to go to deep and hit aluminium, then i was able to crush thhe nipple in on itself and turned it out.
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