It may be possible to use a nut splitter to break off the nuts saving the original carriage bolts. Not the new style but the old style. You can buy a vintage “Nutsplitter” by H.K. Porter on eBay which is what I have. I have used it numerous times on my truck. The cutting edges on the tool can be rotated so the tool can be inserted between the channel. I looked at my truck and the tool and it looks like it will work.
Phil Moderator, The Engine Shop, Interiors and Project Journals
1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum