Here's a summary
1978 low port heads, iron
1979 updated to high ports, still iron
1980 updated to aluminum, knock sensor moved to block.
1981 first year for computer
1982-83 EGR used to heat upper carb plenum.
First choice for your set up would be a 1980. 1979 would be the second best choice. 1981 and 1982/83 might work as well.
I might have a spare 1979, but I would not be able to check for a week or so. It weighs 33 pounds, so shipping is a killer. The aluminum intakes weigh 11 pounds.
You also need to do a little work on the carb to get it work correctly.
CARBURETOR POWER SYSTEM - Non-electronic carburetors use a Power valve to enrich the mixture during acceleration or high speed operation (to prevent detonation). This system is modified for Turbo applications. (One reason a Turbo carb is different than other carbs.) The power system works off manifold vacuum. Low or no-vacuum situations open the release (open) the power valve. Most carbs get this vacuum signal from a port with the carb. In a draw-through turbo set up, the carburetor is separated from the intake by the turbocharger. Releasing the throttle when the engine is under boost will produce vacuum within the plenum. However the intake will still be supercharged. The plenum vacuum will close the power valve and lean out the mixture and cause detonation. To correct this, the power system needs to be connected to the intake manifold down stream of the turbo. It also needs to be protected from boost pressure. (When the intake is pressurized, the power valve should receive no vacuum and no pressure). This is accomplished with a Power Enrichment Control Valve (PECV) or Turbocharger Vacuum Bleed Valve (TVBV).
