aluminum is easy to repair. if the rest of the head ie valve guides,seals
etc is in good condition just have the hole rewelded and ground smooth
it may need a resurface if its on the head mating surface. if you have alot of erosion in the water jackets it may be better to chuck it and get a rebuilt one.
you didnt say exactly where the hole was located
is it around a water jacket? if so someone in the past probably added
some bad water to the radiator. it could have had alot of iron in the water
and they also could have never changed the anti freeze.
do yourself a big favor and always add de-ionized water.
that stuff thats boiled. it removes all the minerals in the water
and if u cant always change the anti freeze get some of that corrosion
booster stuff in the little can. its a white stuff made by prestone