I hate this website... I'm now looking at picking up a wrecked 2004 chevy 1500 to drop the 5.3 and 4l60 in my 57. I was looking up 383s and kept seeing everyone talking up the ls 5.3 conversion for reliability and milage and even power. Plus I never realized that I could get a whole powertrain will all accessories and belt for less than I'd be paying for a rebuilt trans and rebuilt long block.
I love the simplicity of the old school stuff but this might be a fun route.
If anyone knows of any fitment or clearance issues I'd love a heads up.