return line for fuel injection on '73 blazer

[boots]

Scored a HOlley projection unit all sensors holley intake software etc etc etc, though I did have to go out and buy a fuel pump block off plate oh darn! I have a whole $10 invested in the works. Planning to put it in my '73 when/if I ever get a chance. I'm curious as to how to run the fuel return line. It's been a while since I've had a chance to work on it but I don't recall a return line on it. if there isn't how'd ya'll run your returns? My current thoughts are:

T into the vent line that goes up to the cap
T into the supply line between the tank and the electric pump
weld a bulkhead fitting onto the tank itself for a fitting


all those are assuming I'm not forgetting there was a return line off the pump

 

[loafer]

Don't T into the supply line.

I ran 3/8" ID fuel line for the supply and the return, the minimum ID for the return is 5/16". Mine is an 86, so it had a factory 1/4" ID return line, but 1/4" is too small for a high flow fuel pump and will result in back pressure at the outlet of the throttle body (not good).

I removed the fuel tank on mine and drilled a hole in the top of the tank and installed a bulkhead fitting for the return. To be safe I sponged all the fuel out of the tank and then purged it with CO2 before I drilled it. Drilling a steel tank full of fuel vapor is a bad idea.

 

[HarryH3]

I did it on my '75 when I went TPI. Just removed the sending unit and drilled an extra hole, then added a bulkhead fitting there. I used 5/16's steel brake line to make the run along the frame from the engine back to the tank.

 

[boots]

Well my tank has been out for almost 5 years in various weather conditions. Planning on using a tank prep/sealer from eastwood to recondition the insides. Heck right now I'm not even sure where my sedning unit is but I can pull one out of my '75. Drilling/welding shouldn't be much of a problem, can still purge it with CO2 or 75/25 welding gas if you think appropriate. Anything else I should do in the rear while i have the tank out? already swapping body mounts and installing hitch.

 

[chevyk2500hd]

The bulkhead in the top of the tank is the way to go.

 

[BobK]

I "t'd" into the fuel filler neck.Made a "T" with a barbed fitting screwed in place.Then I ran a piece of rubber fuel line from the 5/16ths hard line to the "T"