IIRC the Walbro doesn't come with a venturi port. You have to buy one that has been modified to add the port. I can't recall if I got mine through Intense, ZZP, or W Body store - but at any rate all they did was drill a hole in the top of the pump and weakly glue or screw in the venturi nipple. The nipple broke off as soon as I tried to mount that black line. The black line wants to come in at an angle, so I used the JB Weld for repairing gas tanks to glue the nipple back on at an angle. It came loose again, but didn't totally come off, and I've been running it like that for a couple years with no problems. Other than that the pump won't hold pressure in the line when off, but that seems to be an inherent problem with the pump, not the mod. Turtleman switched to an even higher flowing pump that does hold pressure in the line, but I can't recall the brand off the top of my head. If it comes with a stout, properly manufactured venturi nipple I'd recommend it over the Walbro in a heartbeat.
One other thing, if you haven't mounted the white accordian line yet you are going to be hating life real soon. You really need three or four hands for that job, and a +10 resistance to heat. You only have about one second between the moment that plastic becomes malleable enough to slip over its nipple and the moment it melts away, so you might want to have spare lines handy when you do this job.