You may not have a 283 manifold, sounds like it's a post '68 manifold, since it doesn't have the filler. Also, the original carb would have been a 2 barrel, so the filter won't fit unless it has been modified. I believe that most smallblock manifolds do interchange, though. The "Edelbrock" carb is a relatively new item, based mainly on the Carter AFB, which itself wasn't in use until the early '60s, mainly on Chevy and Chrysler performance cars (SS 409, 413/426 Max Wedge, 426 Hemi, etc) and would not have been OE on GM trucks.
