"large file transfers between VLAN 43 and VLAN 367 are
causing latency due to the high serialization delay of these larger packets"

My thought was that it was referring to FTP. Leaving the acl :
permit ip 139.1.0.0 0.0.0.255 204.12.1.0 0.0.0.255

encompases well.. everything from FTP, HTTP, SMTP...to anything/everything.

Any thoughts ?
Thanks