I just finnished modifying my v covers to use a tank. I used a 2" long piece of aluminum round bar stock, bored and tapped the center to 1/2NPT. I then machined the outside dia down leaving a 1/2" shoulder to sit against the top of the thread in filter holder and the rest just small enough to fit inside the thread in filter holder. I cut a pair of grooves into the machined down section for O rings. I drilled and taped a 1/4NC thread thru the outside and used a grub screw to secure my adapter to the v/c screw in adapter. This allowed me to use the screw in valve cover filter adapter and connect it to #12 AN with a 1/2NPT to 12 AN adapter and out to a puke tank. No cover mods or welding needed. Nice tight seal due to the O rings and it looks pretty good too. Total time with a lathe and a drill press about one hour.