440 will not run Please Help

[Jonas Nordstrom]

The 440 & SB dist are close in length. Not sure which, but one is slightly longer.
Could it be the wrong dist?

This. Check length of dist shaft so it doesnt bottom out into the gear slot when you tighten.

 

[Daves69]

The 440 & SB dist are close in length. Not sure which, but one is slightly longer.
Could it be the wrong dist?

Might the SB vacuum advance be working in the wrong direction?

 

[0DegreeEngineer]

Ended up changing distributors and ran fine until yesterday now I have no spark, I changed my coil and resistor, checked my points all look good can see a small spark at the points, coil delivers spark when cranking but no spark detected at coil wires, no carbon tracking in cap I am at a complete loss