Yes, double pumpers have two(2) power valves and you have to change both. I went through that years ago and got no answers from all the geniuses I knew. Then, I ran into a guy at the Holley display at the World of Wheels show in Chicago trying to hide all of their big, fat catalogs from me as I walk towards him. I don't know who he was saving them for but I got one from him anyway. Get your hands on one of those. There is more info written in plain English than you will ever find in all the how-to hot car mags combined. You need a vacuum guage. Put it in drive and stand on the brakes and read the guage. You need a power valve lower than your vacuum reading. Depending on the source of your advice, it's either half(1/2) the reading or 1.5-2 lower than same reading. Either way, you will get the result you want. I was going through the same thing. Raw gas was just washing down the cylinders and puking up the oil in no time. I finally installed an old 600 with vacuum secondaries that I just happened to already have and a 2.5 power valve just to see if that would work. It worked. Clean oil. No problems. Now, I run a an old 3310 750 vacuum secondary carb with a 4.5 power valve. No problems. I did pull the motor after that. The bearings were junk. I could see the copper in one of them. Luckily, the crank was still OK. I had it looked at for assurance anyway. I installed new bearings and used the same rings. Motor runs great and doesn't consume any oil. I wouldn't junk the double pumper yet. Just because the 'experts' recommend vacuum secondaries for automatics, it all depends on your car. Get your power valves changed and go from there. Holley has an installation DVD that comes with their carbs now, I think. I got one at a parts expo last year. See if you can get your hands on one. I think you can view the same on their website. And, get their catalog if you can. There is a wealth of info in there. You'll make it work. By the way, I just ordered an HP. Can't wait.