from a 2bbl to a 4bl?

OK here we go. I changed the manifold on my 69' 350 cutlass S from the original (held a 2bbl) into an edelbrock 3711 which is the correct version. Here is the kicker - It looks like there was an EGR valve on very back right (pass side). On the new manifold the threaded port is twice the size of the old port (orig manifold). What the hell is this port for and what the heck goes into it? Water? The drivers side has a similar port but its a 1/2" size. Help on both of these freaking holes! "

OK here we go. I changed the manifold on my 69' 350 cutlass S from the original (held a 2bbl) into an edelbrock 3711 which is the correct version. Here is the kicker - It looks like there was an EGR valve on very back right (pass side). On the new manifold the threaded port is twice the size of the old port (orig manifold). What the hell is this port for and what the heck goes into it? Water? The drivers side has a similar port but its a 1/2" size. Help on both of these freaking holes! "

go to www.realoldspower.com and post this Q as they will be more likely to help. I have a E-brock RPM intake but mine doesnt have EGR passages.....sorry