Best Kept Secret in the Big Block Mopar World

That "secret" has been out a few decades or so.
I need an affordable big block for 64 Savoy build. Any. If the running 383 does not materalize, I have a bud close by, with a complete 400. That will get the nod. Only affordable 440 core I have found is a stuck RV engine 6 hours away, one way! Probably NOT!
Seems like the last number of years, all you hear is BIG 440 builds. A 400 will work for me and it darn sure does not need stroked! But I'm no racer.