bleeds in general
Title sounds like leeches in hospital....In my own experience you can regulate pressure through a fixed size orifice in a return fuel hose/pipe after the carbs but the line pressure feeding the carb valves will vary somewhat (how much?depends on the setup)but usually not detrimentally if set up right.The biggest overall pressure disparity being usually from idle to full throttle(not written in stone).Some over and under 1000hp drag/street cars use fuel bleeds on their carb systems,,,,theres umpteen variations of fuel system pressure/volume regulation methods that work for their owners,,,,,,,,,,,,,,,,,,,,,,,,,,,try em and read up on em.
If you drill or select the correct bleed orifice size to provide the correct min and max pressure flunctuations of the carbs pressure requirements there shouldnt be a problem.You can setup this balance by using a pressure gauge temporarily mounted so as to be seen from the windscreen or a correctly mounted dash fuel pressure gauge and read the pressure from the hose/pipe going to the carb/carbs inlet,making sure to go through all the throttle opening ranges while actually driving.We used to use holley carb jets as restrictor bleeds and if one was very close in size to what was needed we would put a radiused profile on the entrance and exit (to increase the flow)of the bore to save drilling up a size with fractional drills(if the size needed wasnt available).Our bleed systems were mainly done to prevent vapour lock and make life easier for the pump to stop deadheading,especially for street driven cars.Still not as easy/quick as purpose built bypass regs,but if you have the time and inclination,,,,,,,,,,,.There may be a very fine incremental adjustable fuel compatible tap available,,never looked.You can also modify/machine easily,standard holley deadhead regs to bypass types but thats a different subject.PS.earls uk can get hold of holley bypass regs(12-803bp)if you phone them,for £80 all in if that interests anyone.
