Hello, I'm new to the forum and would like to give a howdy from Indiana. I just recently built a 454. The motor is in a 1981 GMC Crewcab 1 ton 4x4. I had a friend help me pick out the parts on this project (he knows alot more than I do). So anyway I put the motor in and were told the cam was a crossfire cam and you had to switch the #4 and #7 plug wires. My buddy's were confused because they never heard of this before. We have it running but we can not get it to idle right, we messed with the carb and tried to set the timing but with no luck. Once the motor gets warm and you shut off the truck and try to restart it, it cranks very slow (like the timing is off) and eventually start. It will not sit there and idle, it will rev up and then slow down, like its hunting for the sweet spot. I have asked all my gear head buddy's and no one has any clue on the problem. Any help or ideas will be appreciated. Thanks!!