Instead of buying a 400 just put that money in the 440. Don"t worry about weight the engine you build wont weigh the same as a stock 440 unless you build to spec.I built my 440 in my living room and me and my brother lifted it out of there and into my truck. We also weighed the car and right now it weighs 2720. I am hopping to get it to 3000lbs when everything is done. The only thing on it that is fiberglass is the hood. Both are vary engines but you allready have the 440. Mark