Found this 383, worth it for my 65?

Demonracer said
You will have to build the front suspension to handle the weight difference, (i.e. torsion bars, disc brakes, etc.) it's doable but like TMM said you'll be better served with a healthy small block.

You can lose a lot of weight with just aluminum heads, intake and headers.

Do a search for Put your Big Block Dart on a diet or something like that.