flexplate bolts?
Then you need to keep the flywheel from turning. Usually clamping a pair of vise grips in the ring gear section so when it turns it hits the block and stops so you can get a straight shot at the bolt.
So many people strip these out and I'm assuming because they put a socket on it and turn, the socket stops the flexplate from turning and also pushes it sideways in the bolt and strips it out.
I've removed a bunch of 4L80E's that have six bolts, plus LS1's with 8mm allen head and 15mm hex head and never stripped one out, never used heat or air tools.

