Being fairly knowlegeble of automotive repair, I'm about to tackle a Northstar with a blown headgasket. It's a code 'Y' motor (I believe) in a '97 Deville.
I bought a code Y motor (so I think) from a '94 Seville that has good compression. I believe I can swap the intake hardware and wiring an make the transplant, but if I decide to repair the origional motor, I've heard something about needing 'Timeserts'. What are they? I recall Timeserts were thread replacements similar to Helicoils, so why do I need these for a headgasket repair?

you will find stripped theads on most blown head gaskets one or more bolts on tear down. time-serts are inserts that hold far better than a coil. howerever after doing two blocks and having some of the serts pull out of the soft metal (from prior over heating) I now use serts only on cross thred or force stripped holes with no problem. 94 to 97 not a good match due to head and intake changes. hope you are doing this for hobby work as it ant easy. sts96

Yea, this is just for fun. I keep telling myself that. And yes, I'm finding out that the '94 motor is different from the '97. Was hoping to swap the induction setup and electricals, but the bolt holes for the induction system are different. Pisser.