Flare to banjo, to drill or not to drill?

I have some four pistons aluminum calipers from a 89 Mazda RX-7 that I'm planning on using for a differnt application. The calipers are made to use a flare fitting, and have a flare surface inside of the line hole. I am planning on useing a banjo fitting on them, and I was wanting to know if I should drill out the flare surface inside of the hole to allow for better fluid flow, or should I leave it in? Drilling it out wont be a problem as they are going to be disassembled and rebuilt so all of the metal shavings will be blown out and their will be no worries of accidently drilling into the piston. If I dont drill it out their will will be plenty of threads for the banjo bolt to hold to so there is no worrys of it fitting, just wanting to know about fluid flow.

i don't think fluid flow will be a concern as brakes don't move a large volume of brake fluid at one time. you may do better to go to a hydraulic shop and have a fitting that works with your application put on one end of a hydraulic hose, and the stock fitting from the mazda's brake system on the other.

Thats what I had origionally planned on doing, just having a line made with the same fitting as mazda used from factory, but I need a 90* bend there due to clearance and that would not be possable. I know fluid flow into a caliper is minimal but it will be setup with a Willwood fluid recirculation system where fluid flows from the caliper back into the master cylinder though a secondary line plumbed though the bleeder. With the flare inside the fluid line I dont want it to cause stagmentation there which would cause the fluid at that spot to be hotter than the fluid in the rest of the caliper.

Your plan sounds fine to me. I think drilling it out would be unnecessary, but wouldn't hurt a thing.

Upon disassemble two of the bolts holding the two calipers halves together siezed up and snaped, so while I got to drill them out I'm going to go ahead and drill out the flare.

Just a dumb thought; if you drill the flare oversize by like 1/16", you could increase the flow considerably (much more than required) and still probably have enough of the flare surface left to run a flare fitting if you need to in the future.