Any V8 in that chassis is going to have fitment problems, mostly involved with steering column/exhaust interference. Work-arounds involve offsetting the engine to the right, moving the steering gear to the left, or a total rehab of the front end for independent suspension. Some people install a Saginaw power steering gear ahead of the axle with a Rube Goldberg Pitman arm setup.

The 409 is wider and heavier than a small block engine, and hotrod parts are scarce and expensive. There's somewhat of a cool factor to the scalloped valve covers, but it comes at a hefty premium in difficulty of installation!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!