I bought it with a rebuilt 454, 1000 miles. Many of the carburetor's connections have been plugged or cut (fast idle, vacuum). Mpg is awful at seven highway and maybe eleven city. A fellow 4x4-er said it has a newer carb (std Chevy, not Holley or Edelbrock), and many of the pollution devices didn't exist on older engines. This doesn't sound right. Any suggestions on the kind of shop I should take it to, and questions I should ask? I can maintain what I've got, but when it comes to missing parts, I am lost. The only 4x4 shop in middle TN does well on suspensions, etc. But I didn't see any tune-up equipment in the bays.