With the crate 350, stock quadrajet and quadrajet manifold (both original to the truck), dual exhaust with stock exhaust manifolds, th-350C, 2.56 rear gear and off brand tires:
16.8
With the LG3 305 (out of a 78 malibu) , rochester 2g carb and 2BBL manifold, dual exhaust with stock exhaust...