340 or 408

A 400hp 340 will make that at 5800-6000 a 416 gonna make that about 600rpm less, the 416 gonna make about 60 lb-ft more than a 340 so if both engine are gonna run 3.55:1 gears the 416 will run stronger but if you go 4.10:1 for the 340 the torque to the ground would be the same. If your going with auto and 3.55 gear I'd go 416, personally I'd do a 4 gear swap and 4.10 and keep it 340.