Never heard of an intake problem on the 5.7 or 6.1. That's not to say they can't have one, but I don't believe it is a common issue. We have several at the PD I work for, and none has had any motor issues, and they get beat to hell. The highest mileage one now has close to 80K miles. Alot of blue smoke is obviously not normal. As mentioned, leak down test is probably going to be next step. Curious, is it losing oil or coolant?