rear spring perch issue
 

I am trying to put frame connectors on my 81 camaro. And the 3 bolts from the front leaf spring perch. just turn in their spot i managed to extract 2 out of the 6 they came out just like they should but now im stuck cause from what i can tell there is no acces to the other side of these bolts. Do i need to cut floor pan or frame i have no idea how to fix this prob any advice would be great.