I'm in the process of rebuilding my 1275 for my innocenti. I bought the competition head stud kit from minispares for the 11 stud head. In the instructions, it says to drill an tap the water pump side stud hole (where the one head bolt previously was) from the existing 5/16" upc to 3/8" upc. However the hole has been helicoiled, not sure if thats from factory or as a result of a pulled stud. I removed the helicoil, and tried to thread the stud into the "un-helicoiled" hole. It began to thread smoothly at first and then about half way down it stopped. I tryed to run a chaser by hand and same issue. I understand that helicoil uses a special tap (sti tap i believe), but would it be possible to run a 3/8" upc tap through? Or am i better of redoing the helicoil and running an ARP head bolt? Thanks!