Yeah, you can see the header is cracking due to it being under pressure or force.
is the flange that bolts to the head one piece ? or 4 pieces that bolt to one cylinnder each. if one piecve cool, if 4 pieces then yes any clevo head will doto bolt them to when welding.
quite often pipes crack due to weight sagging on them.
as for drilling the holes that is great idea even a 1/8" hole each end will do, yes it will leak,but the crack is leaking anyway.
good luck !
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