Access holes for bell housing bolts

Thanks for the replies, I guess this is not a common practice. My plan was to put body plugs in the holes. I’ll either try the stud idea or put the bolts in with the engine tilted back. I took them out with the engine and tranny still in place.
I’ve been drag racing for 35 plus years and I understand the purpose of the firewall and how even the smallest hole can be an issue. I’ve always been a small block guy, this is my first a body with a big block. Things are a lot tighter!