440 or 400???

The 400 is easier to install and is slightly smaller than a 440.Your car came with a 440 from the factory and does not need fenders cut to install a 440 or headers installed,some one is giving you a line of B/S.I would buy both motors and build a 451 stroker motor.Use the 440 crank and rods and the kieth black stroker pistons.Weather you go with the 440 or 400,I bet you will come out to the same price within a few hundred dollars.The 451 we have in my bodys challenger is crazy,with the six pack and good cam and gears and a bit of convertor,niece tire frying combo.I would build the 400 motor with the 440 crank and rods.and what ever was left over,I would sell or keep for a nother project?mrmoaprtech