The truck is a 1980 Chevy K20 with 350, Edelbrock intake, Edelbrock carb and here's my problem. The truck starts fine cold or hot, but she starts bogging at around 15mph to 35mph. (Loss of power comes first and then the bogging.) I started having this problem a month ago when I still had The Holley truck avenger carb, but I was having many different problems with this carb from day one, so I went out and got an Edelbrock performer. The problem went away for about 3 days but just like a bad cold, it came back. So, I got a new fuel pump, fuel lines, fuel tanks, wires, plugs and distributor. I changed the intake gasket and I triple checked the timing. There are days when the truck runs like a clock and there are days when I can't drive it out of the driveway because of this. I had to have the truck towed from the office parking lot last week because I couldn't drive it. The shop had the truck for a week, drove it for 120 miles, and couldn't find anything wrong with it. This is driving me nuts and before I drive it of the cliff can anybody give me any ideas of what I should check/fix?