I have 76 Datsun 280z that has been switched to Holley 390cfm 4bbl. I purchased a new Bluetooth 123 distributor and installed and wired it according to instructions. It will start but backfires and runs erratic if you bring the Rpm up. I’ve seen several you tube videos of the exact same problem but have not seen any on what to do to fix the issue. Any ideas out there?

Did you disconnect the old ignition module by the fuse box? You might have dueling ignition modules. The 123 has its own internal ignition module.

Give some detail on your car. Has it ever run right for you?

Do you have an appropriate spark map loaded? That sounds like the advance or timing is incorrect