Headers question

I am currently building my 73 Duster and accumulating the parts for a 10 sec build and have a question about headers. I think I want to go with 1 7/8 primaries but the choices are slim from what I can find. How bad would 1 5/8 or 1 3/4 primaries hurt the performance? What headers are you guys running?

Here's the build specs.

• 408 forged stroker
• Forged flat top (CR around 11:1)
• Solid Roller Cam (still deciding on the grind)
• Ported Eddie or Speedmaster heads (depends on which set works out best)
• Ported Victor340 intake
• BG Race Demon 750

Built 727 with 4200-4400 stall PTC converter

Narrowed 9" with aluminum dropout, True Trac and 4.11 gears

28x10.5 slicks

Total weight should be around 3000#


Thanks in advance!
Bill