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Discussion Starter #1
,,I have a q-jet feeding a small engine in a '65' with the 5/16" line from the tank, then I change to 3/8" line bent up to the carb,,? could the larger line after the pump make the pump struggle to feed the carb on wot?,, kinda like feeding a firehose with a gardenhose,,,
 

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No but it could be starving from the tank to the pump. How old is the fuel pump? RICK
 

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I am going to say no not unless the pump is weak. If or when replacing pump then replace it with a high volume mechanical if you run it up pretty hard.

I ran a 5/16" (factory 3rd gen for a 307 car) on my last 71 Nova running a 406 without any issues. I did sump a new tank and run a 1/2" hard aluminum line and up to the carb with a #8 AN fittings and braided hose. After the change and going from a 3000 stall to a 3500 stall I only picked up 2 tenths in the quarter mile running 11.60s. Never ever did the car lay down not even with the smaller line. I estimated my setup to be 500ish hp. I am guessing probably around 550-600 hp would be a problem though.
 

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Discussion Starter #4 (Edited)
I am on the other end of the spectrum,,, this is an inline,, 250,, lotsa stuff,,Cliff Ruggles built this carb,,, it had originally worked, a few years back,,then it began to hiccup and now with so many tweaks and changes I am starting from scratch,,, the pump is new,, the car runs well with continuous load on the engine it pulls till it is too fast to think the drum brakes will work in an emergency,,but from idle or stop to w.o.t. it starts to break up right at high rpm like it is running out of fuel,,I've gone back through adjusting the airvalve flap opening rate and such and smoothed it out a bunch,, but not back completely,,i have stared at the fuel filter (glass) in front of the pump, it appears to suck itself dry, but the fuel must just feed thru the tube instead of filling the glass,, so I thought maybe on load it was sucking air,,,I removed the filter,,still one in the carb,,I put it back in after I bent the hardline,,now I am thinking maybe the orifice that feeds the secondary fuel well is plugged maybe and not
giving the fuel needed at vacuum drop,,?,, the fuel lines to the rear were clear,, new sock,,,tank vent? it looks as if it just goes to the filler neck,, without the gas cap it is the same,,
 

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Pull the gas cap and blow the fuel line from the fuel pump back to the tank. If it is too clogged it will blow or rip the sock off inside the tank which is fine. Put a new metal filter (no glass or plastic please) and a new fuel pump if any doubt or problem.
 

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This sounds similar to what I'm experienceing with the dual carbed 194 6cyl with 5/16th lines in my 64 nova right now. It stumbles and acts like its starving for fuel crusing at highway speeds. I've got rust issuies with my tank and I think the sock filter on mine is plugged up because I don't seem to be getting enough fuel to the filter right before the new pump I have on it. Ran fine untill yesterday after I changed the inline filter because it was pluging up and starting to have occasional stumbles at speed last week. now its constant and I can't get it to move faster than 55mph. If I close the chokes at speed ( richening the mixture), it will level out and run smoother but not perfect. So it has to be a fuel delivery problem. I would suggest checking the tank, sending unit and the main line from the tank to filter. Which is what I plan to do. The glass filter you mention should be full of fuel when running. If its sucking dry them somthing further back in the line is restricted. I know when I ran one of those glass filters temporarily before installing a metal one that it would be full of fuel when the system was working right.
 
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