Another slow 340

I think the air, and the gears are your main killers there.... that and spinning the tires lol.

Already sounds like you got a good plan worked out, I think you'll do fine.

Just for reference, almost an identical combo (Duster, 340, 10.25:1, M1 intake, 509 cams, J 2.02 heads) ran 13.4, with a 3500 stall converter.... but that was at sea level