Asked in Chevy 350
With Ignition coil and resister new and still have weak spark and engine wont start?
If it's a HEI system you probably have some kind of problem with the control module. If it's an older engine using points I'd look first at the points and condenser.
The resistor is only used when the engine is running. The starter shunts full voltage to the coil during startup to provide a little extra spark. In effect the starter bypasses the resistor for you, or at least that's the plan. Verify that the starter is doing that before you spend too much effort on anything else.