Not to be too harsh here but...
I strongly suggest you get your stuff together with regard to fuel lines! Braided hoses may look nice and all, but they won't help your car go faster, and they darn sure won't help in an engine fire!
This is a plumbing forum, not an automotive one, hence the lack of responses when you mentioned that you're using AN -6 braided line.
Anyhow, you're never going to get the primary benefit of braided hose (high pressure capability) by using hose clamps on it.. What you should be using are actual AN fittings, like these:
an hose fitting - JEGS High Performance
The right way to do this is to use the proper sized flared fitting and given that this is for a performance fuel line (even in a Civic) you probably want to use 3/8" hard line since that's closest to the size of AN -6. Here's the fitting:
JEGS 100106 - JEGS AN to NPT Adapter Fittings - JEGS
I know this probably doesn't answer your question, since I doubt you intended to replace the hard line in question with something better, which will require some flaring tools and a steady hand. Of course, you haven't mentioned what size the hard line actually is, which on the Civic may be 1/4" (???), and there is a legit -6 to 1/4" fitting:
JEGS 100104 - JEGS AN to NPT Adapter Fittings - JEGS
It is NOT a good idea to "bush" or otherwise try to make a too-big hose seal or clamp to that hardline, as your car is fuel injected, with the pump in or near the tank. That means this line carries around 60 or more psi. A leak is too dangerous to risk, in my opinion.
Sorry if this comes off as uncool or harsh, but it's the reality. Please get the correct fittings. A complete kit for your car from filter to fuel rail is only around $75, which will seem like a really small price if you're standing on the side of the road waiting for the fire department to come put out your car.
Honda Civic Russell Stainless Steel Fuel Line Kit at PRO Civic.com
~aaron
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