Hi Skip, welcome...,
Ditto M5's advice.., however you could give a bit more info. to help us help you. i.e. "will not start"
could mean eng. doesn't turn over when you turn the key to "start". OR it could mean the eng. spins when you turn the key but does not "come to life/fire up"..!!
A few drops of fuel down the throat of the carb., then turn the key (assuming the eng. rotates) will tell you if it's a fuel or ignition issue. If it attempts to run.., it's not the ignition..., it's a fuel issue. No fire.., it's ignition issue.
Have you R&R;d distributors B/4..? you may have it in 180deg. off or somewhere in between.
Can you give us some info. about your mech. experience..? And, any other info. about your rig & any other mods relating to engine setup..? Assume this is a V/8.., is it auto or stick.? Is it a stock 302, etc.
(I'm not sure what a "Duro spark box" is) (Is this an Autozone ignition module.?)
Point being, it's really tough to solve these issues without knowing the specifics.
Don't give up.., it's probably a simple fix.