What carb?
Well, witht he 4200 stall, you can go with anything, really. I dont agree that DP carbs make more power. The right carb, will make the most power. At 4K+, both carbs will be wide open, and the vaccum carb will be better on the street in terms of response and milage(ok, milage aint a big deal..but....lol). The DP can be tuned to be as sharp as vaccum, but most guys dont pay enough attention to tuning to get it that good. Two weeks ago, I swapped a swap meet 3310 (rebuilt and tweaked by me beforehand) for a jetted and powervalved 650 DP on a basically stock 383. The owner didnt believe me, so I had him make several passes before I switched them. The car went from 14.8 @ 92mph to 14.1 @ 95 with no other changes. The 60' only had a .01 improvement..it was all in the smooth application of the secondaries, as oppose to a second large accelerator pump dumping excess fuel, and the engine then recovering from it.