Stop in for a cup of coffee

the thing I need to find out because I keep getting different answers

a 63 A-body only came from the factory with slant sixes ....Soooo to put a V8 in, would you need to modify the firewall or is it ok as is .

someone said you need to dent the firewall in to clear the distributor on a small block and someone else said it's cool to go as is.

which one is right??