Sorry to hear about your bad experience. I have an 8350 and it has performed flawlessly for more than 5000 miles. I also run an EFI. The FAST EZ-EFI. My only complaint is that the 8350 is too tall to fit under the screen, but I solved that with a neat mod with a 2010 Mustang shaker scoop.
Did you bypass the ballast resistor when you changed to electronic distributor?
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