383 vs 400

As a heads up-Back in the day (ya I am that old) you could get the 340 sixpack to run harder that a 383 HP. It was lighter and the car would handle far better with the 340 as well- a win-win. The 400 was a smog motor to replace a 383/440 with and the stock ones have a cast crank. If you are using a 440 crank in a 400 block why don't you just bore out a 440? FYI the 383/413/440 motor home engines had a higher nickel content and the "motor home" heads with the extra water jackets around the spark plugs to help with any pinging problems.