swap on vortec heads :lol: that would be one way to do it :lol:
the only "non-permanent" way I can think to do it right now is to find the diameter of that hole and get the correct pipe tap to thread it (if one exists). I dont know if the hole would need to be enlarged to accomidate the correct tap or not.
Next, I would get an allen socket style pipe plug, put some anti-seize compound on it and thread it into the hole. Once it stopped threading, I would grind it flush to the manifold (provided it left enough socket depth to allow it to come out again) then I would put one dimple in the metal on the edge of the thread as to now allow it to work loose on its own.
Ok, now that I looked back at what I had written, that really doesnt seem like an easy or less damaging way of doing things, so how about a "Semi-Permanent" way of doing it.
Measure the diameter of the hole, make an aluminum slug that fills the hole, bevel the surface on the slug that will be facing the gasket surface and have someone tig weld it in there, then clean up the surface if needed. When the time comes that you need to remove it, center punch it, drill it out and clean it up. Presto, all done
