Encountering the same dilemma on an engine I was rebuilding for a customer, I identified the thread type, diameter and pitch__it's a rare one__and some dark musty warehouse still had a Helicoil repair kit for it (of dozens of thread insert kits I have, this is the only one packaged in a cardboard box). If the kit included ten (10) inserts, then I probably still have 8 or 9 left!
If you want to send me your pedestal and cover the return postage, I'll repair it for you. You could consider it a Christmas present, though no guarantee you'll have it back by the 25th!
ALWAYS, always "start" the banjo bolt into the pedestal, with the copper sealing washers, before attaching the pipe to the fitting in the head. You'll be assured of getting it in straight without it being in a bind.
BE CERTAIN that the hole in the rockershaft lines up with the oil feed hole in the pedestal before inserting the banjo bolt__do not use the bolt to correct a misalignment!
Final tightening with a torque wrench after everything else has been assembled & torqued. On that day, I knew what that torque was, pity I didn't annotate the picture with it...
I have in the past, particularly on engines that are expected to be operated at frequent and/or continuous high RPM, welded up the orifice in the block fitting, redrilling it for a reduced area, thus avoiding flooding the top end and starving the mains & rods of oil. Healeys were still
daily drivers back in those days, I suppose they live more sheltered lives today!