[rfmaster]

Originally Posted by Jonboy

Just a quick fuel question, for a swap into an older vehicle. I am getting ready to help a friend do a TBI swap into a '74 Blazer, but it does not have a return line. What is the best way to do one? Should I use rubber line going back to the tank, (and does the return need to be FI rated?), or does it need to be hard line. I am planning on using an inline fuel pump and using the original feed line. Also, where are you guys putting the fuel filter when doing an inline pump?

1) You'll have to become a plumber and install a new 3/8" supply line - for example SUM-G2538 aluminum fuel line which is easy to work with. Use your old line as return. Do not use rubber line - it will increase pressure drop and will deteriorate over time. As a minimum supply must be 3/8" and return 5/16". Return is a low pressure, but it still carries fuel. When plumbing vehicle for EFI keep safety and long term maintenance in mind!!!

2) If you have a baffled tank - use in tank fuel pump. In case of conventional tank use largest fuel filter you can find before inline FP inlet port. Large fuel filter will act as a mini surge tank and prevent fuel starvation when fuel sock gets uncovered. It is not a perfect solution, but it is as close as you can get away with without building a full surge tank system and lift pump.

//RF