Sending Unit. 5/16” or 3/8”, ‘‘tis the question...”


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Getting ready to purchase a sending unit for my ‘61. It has a 283, stock build, with an Edelbrock AVS2 500cfm carb. I know the 5/16” sending unit and fuel line was stock for 235 and 283 engines, but is there any advantage for me to bump up to a 3/8” unit and lines? (I’m also replacing the entire fuel line, stem to stern anyway).
Thanks ;)


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Supporting Member 1
The prebent 3/8 line goes under the passenger side a frame to get to the fuel pump.
The 5/16 line runs along the frame by the exhaust manifolds to get to the fuel pump

i used nothing but stainless prebent 3/8 inch lines ( no rust ever)
Paul, I am going to use nicopp 3/8 tubing since I don’t have the body off the frame. Been really happy with the flares I’m getting and how easy it is to finesse into the tighter bends as far as brake lines go. I’m afraid that trying to snake prebent fuel and brake tubing from the through the center of the x frame would be virtually impossible.


I guess I'll throw this in... When I put a 454 in my 72 Chevelle, I ran it for a few years with the stock 5/16" line and all was fine. I have upgraded to a 3/8 fuel sender and lines a few years ago and never noticed a difference yet.

Now for a race car, I'm sure that extra fuel flow would be needed but for street cars, it might not really be necessary. Especially for the original poster since he's got a 283. Just my thoughts for what that's worth. :D