How to remove 1929 Coupe cowl blocks

[walkerlakeprinter]

I finally got my new body blocks for my 1929 Coupe, but I can't figure out the best way to remove the old cowl blocks. There seem to be what's left
of the two rear-most bolts that have either sheared off or rusted off when the body was lifted off my frame about 6 years ago. I'm assuming what is shown on the attached photos is the top of the bolts that are still sticking at least partway down through the wooden blocks. I don't have the body up high enough to visually see what is going on down under, but I can feel holes going up from the underside. Any suggestions?