Is this for your '65 short step?
On a truck like that I think dropped spindles are the best choice but I'm not sure if they allow you to keep your six-lug brakes.
What rear suspension do you have? Most '65 Chevy trucks will be the long arms with coils, but some are leaf sprung. Most '65 GMC trucks will have leaves, but some are coils with the long arm.
The best answer to your question does depend somewhat on what truck you're talking about and how its sprung.