400's are they any good?

Anyone have any ideas for one going into a 68 B-Barge Coronet 2 door? The car has a tired mild built 68 318 (cam, headers, intake, 4bbl) with 2.76 gears. I have been told it could be turd even with headers, intake, Firecore ignition system and convertor? I am hoping I can get some 3.23s in the rear for free but, we'll see. I already have a supposedly running '74 400 and 727 I bought for somewhat cheap . Been looking for a decent late model 440 from a car or truck locally and can't seem to find one cheap enough so it's looking like this engine will have to suffice.