FWIW the smallblock in the heads up car made over 1000 with a set of 1 7/8" 20 long primary headers on the dyno. Headers on the car are 1 7/8 to 2 to 2 /18". Car ran 8.0's last year at 2800.
had some headers built...1 7/8-2 1/8-2 1/4..didnt see much performance diff..converter made all the diff
