Here is the "pressed/pinched" carriage bolt in a GM NOS replacement front plate for a 1954 235 engine.
Here is a top view of the bolts. Sorry about the poor photos.
- If I had to remove the bolts, I would probably first carefully try to press them out.
- If that did not easily work, I'd probably try to grind down/out the pinched plate metal where the bolts come through the plate.
- If that did not work, I'd probably cut the bolts flush with the plate and then try again to press them out.
