What size is fuel return line?
Thread Starter
Racer
Joined: May 2001
Posts: 401
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From: Carlsbad CA
What size is fuel return line?
I have read that the stock fuel return line isn't big enough for a fuel injection return (at least not one with decent horsepower), but I can't figure out if the stock line is 1/4" or 5/16". Anyone know for sure?
This is on a 1974 small block. Thanks.
This is on a 1974 small block. Thanks.
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
You will want a 3/8 return line. The stock return line will not be enough unless you are running a low po motor. I am probably going to use the 3/8 line from the tank to the pump for the return line and make up a new pressure line. Either 6 or 8 AN depending on your power.
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
All the the return lines are 1/4. The nipple on the pump is only 1/4 so it really does not make sense to use a larger line. The air conditioned cars used return lines to prevent vapor lock. Performance engines from the factory did not use a return line and those fittings are 3/8`s in and out. ..
Advanced
Joined: Feb 2008
Posts: 88
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From: PORT ST LUCIE FLORIDA
returns are 1/4'' i had to use a 3/8 return line on my f.i. because it was holding to much pressure on my regulator gauge , return lines should be at least the same size as supply line , i used -6 line followed the existing lines back to tank , i modified the sending unit removed the 1/4'' nipple and installed 3/8 fitting in the sending unit, works fine
