Testing for spark quality/ "jump" is fairly important. A bad coil/ plug wire/ low voltage/ poor points/ poor condenser all add up LISLE tools makes an adjustable tester that is only about 10 bucks. Again, expect (with a good battery) to see at least 3/8 good blue snappy spark, using a wire from coil to the LIsle--to ground.
Also if you are cranking it by jumpering the starter relay, THIS DOES NOT bypass the ballast resistor for starting, and not using the key to crank it will result in greatly reduced spark power and voltage, because you are "still" going through the ballast while jumpering the start relay
Consider this:
When running and with battery charged and alternator running, system voltage is 14 or so, coil voltage will be about 10- 11V plus/ minus
When starting with the key, with a good battery, battery will pull down to about 11v, and the coil will see.....about 10-11V
Adversely, when starting by jumpering the start relay, and with the battery down say, 11V, and still going through the ballast, the coil will only see maybe 4-5V.
