340 or 408?

They are 2 completely different animals that will have different characteristics. I have raced a stock warmed over 340 that ran 12.67/ 107. It was a dog below 3000 RPM but screamed like a banshee above 3000. I turned that into a 416 that I street drive now. It produces 530/ 524 TQ with 400 Ft/Lbs at 2000 RPM. The 2 combinations are worlds apart. I can leave in 2nd and floor it and your stomach will rise. The torque produced by the 416 is big. Cam is sized for max power at 5900. If you want to have a car that will pull like a beast without having to hammer it, build a 416, but never let anybody drive it without installing a Rev limiter that you can set with a hidden switch. I lock mine at 4000 RPM before I hand it over to someone that is helping me. There will be no street tires that will hold this and the rear will come around so quick, you better be ready for it.