Not to severly deviate the topic, but since all of this good info is here in one thread I thought I'd add this for those of us following along that are in 72 and older trucks.
The below article (see link) has some info on how what the magazine guys did a 5.3 swap in a 68-72 C-10. Specifically what sparked my interest is what they did for the return line. I plan to take it a step further and make a line that attaches to the pipe thread fitting they welded in and dumps at the bottom of the tank and pointed away from the pickup.
I hope this helps someone.
Thanks to the OP and knowledgeable posters for adding thier info. I have yet to start collecting parts, but the TBI Swap is in my top 3 of my short list of things to do this thread will be invaluable when the time comes to start installing parts.
http://www.classictrucks.com/tech/09...all/index.html