I am going to disagree mildly with some of the above posts.
First, on a basically stock 283, whether you use a square bore or spread bore is not going to make much difference for the following reasons:
The original 4 barrel (Rochester 4-jet) used on the 283 truck engine was about 400 CFM (about 180 primary, 220 secondary).
The Q-Jet is 750 (150 primary, 600 secondary). There is not a lot of difference from 150 to 180. The 800 CFM Q-Jets (newer) were used on 454 engines up to 1 ton chassis.
With a basically stock 283, you won't use all of the CFM available from any of the above.
I definately would NOT go with an aluminum intake for your application. Every test I have ever read or conducted show the cast iron intakes perform better at lower RPM's (torque area). If you are going to run above 4000 RPM all the time, then go with the aluminum intake.
As to carburetor, my choice would be an original Rochester 4-jet square bore if you can find one WITH the original cast iron square bore manifold. NEVER make the mistake of using one of the square bore to spread bore (or vice versa) adapters.
Jon.
