[BBC DON]

Can anyone out there tell me if it is difficult to change the size of the fuel line right out of the tank? I was told to change to 3/8" or 1/2" line, but will the smaller size outlet at the tank kill any advantage gained from larger lines to the fuel pump? Thanks in advance, Don

 

[Tony]

I changed my tank outlet to 1/2" on a 69. Drop the tank and remove the sending unit. Now for the part you might call difficult is to remove the factory line. Bend a piece of 1/2" tubing to duplicate to old line. Make the hole bigger so it will fit through the opening. I welded mine into position but brase or solder should also work ok. Just be careful not to melt any of the gas gauge components. I did not use a pick-up screen on the end of the tube. It works good.

 

[cchamber]

Any problems using Aluminum line compared to steel?

 

[jmw]

From a friction loss standpoint, having a 3/8 outlet from the tank will not kill the effect of having a 1/2 inch line the rest of the way. In other words, changing the tank to pump line out from 3/8 to 1/2 will help if you are losing pressure at the carb under full load conditions. Then if you still have problems, you might want to go through the trouble of changing out the sending unit to 1/2. Unless you are running an all out, high RPM race motor, or nitrous, I think a 3/8 sending unit and 3/8 line to the pump will ensure low friction losses at high RPM. What the factory put in an LS-6 is good enough for me and my 502.
John Walker

 

[David Host]

If you go with the 1/2" line, you will have to change everything to 1/2". That means the fuel pump fittings and carb fittings would have an ID of 1/2". I think 3/8" is big enough. If you think the line size is the problem, I would put a fuel pressure gauge on the line close to the carb and test it out. If it goes real low, then you might want to look at getting a fuel cell, 1/2" line and a electric fuel pump. My $.02