" Not getting any spark, I rebuilt the distributor with new points, condenser, rotor and distributor cap. Still no spark, any suggestions?"
Yes.
Troubleshoot the problem before you start buying parts.
Before I offer you some help w/ your problem, bear with me for a minute as I share a “learning moment” for others facing a similar issue.
What you have done is replace good working parts in an attempt to fix an undiagnosed problem. I’ve done that and I’m sure others around here have done it too.
You have spent probably $50 plus hours of time & frustration w/o having the slightest clue as to what is causing the tractor to shut off & not restart. Worse yet, by replacing all of those parts, you have probably introduced more problems.
The one way that I found the best results with is to take a systematic, step-by-step approach to solving the problem, working from most likely to least likely. The trick to fixing these tractors (or trouble shooting any piece of equipment) is to be systematic about it. You need to isolate the problem step by step and work from most likely to least likely. Jumping ahead to 'so-and-so said it could be whatever' or just replacing parts usually just wastes your time and your money. I know it did for me.
You have solved half the problem by determining it is a spark problem. That doesn’t mean you need to replace all of the electrical parts on the tractor! 
Get your meter out. The ignition circuit goes from the battery to the terminal block then to the switch then to the coil. Trace the circuit. Post back w/ results.
(HINT: ignition switches fail & wires come loose a lot more often than a coil goes bad)
I might not be capable of telling you why your tractor isn’t running, but I sure can tell you how to figure it out for yourself.
And if you want more specific advice on finding your problem, tell us if it's a front or side distributor.
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