Any risk of testing the car without the fuel filter fastened to 3 screws Su carburetors (round top) ? How long can you test it without the air box filter on? Trying to get the correct mixture!!

I would never run without a fuel filter. You chance getting something stuck in the carbs and making your mixture project even worse. As far as air filters, you can run without them as long as you stay away from dirty air (dirt roads, driving near sandy beaches, etc). But you also have a risk of sucking in something that may cause engine issues.


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i just want to drive it around to test the fuel mixture is correct.

 IMO, you can safely bypass the main filter temporarily, there are the "last chance" filters inside the banjo fittings on top of each float bowl that should catch any major debris. That said, it would be worth checking them when the experiment is completed to make sure they didn't pick up any crud from the tank.

The thread title focuses on air filters but the question text says fuel filter and I want to answer on behalf of all air filters, world wide, and registered to vote.  Air filters are a necessary part of the intake and fuel / air mixture process.  Not only do they filter out grit and moisture, they cover the intake throat and keep big things from really screwing up your engine.  In my opinion, you will never be able to determine if your fuel mixture is correct if you don't test the system as it will be operational, i.e. WITH the air filter installed (a clean one is preferred).