New fuel system for the Dart

Well the 3 week delivery time turned into 5 weeks. Then while opening the boxes which were in perfect condition, I found the tank damaged pretty badly. Hyperfuel is using Tanks Inc. tanks. I sent pictures of the damaged tank, and a new replacement was quickly sent out to me directly from Tanks Inc.. The new tank is in hand, I am now beginning the installation. I am in the process of fabricating a mount plate for the fuel pressure regulator that will mount it where the mechanical fuel pump would have been.

Last night while laying under car I was trying to determine best way to run return line to tank. My supply line is a 3/8" hard line which was newly installed several years ago, and mounts in factory locations. My return line will be 3/8" also, I bought proper Red Horse braided hose, but am now considering making a hard line. Most concerning is how to get through/around the torsion bar cross member, as I would prefer not to drill it. Ideally, the best location for ease of install would be to drill a hole through the cross member just below the supply line routing holes. Knowing this is where the cars weight is carried, this makes me nervous, as I would be putting holes 1.5" from torsion bar sockets. Am I overthinking this as usual? Additionally, the idea of running fuel lines below the cross member is not appealing. Any suggestions?

I may call tech line today and ask if a 5/16 return line would be sufficient. If so, I may be able to sneak the return line through the existing holes where supply line goes through.

Maybe consider egging out the feed line holes for the return to go through next to it.
You could also reinforce the holes area with an add on plate if you feel nervous about weakening the area.

Way too late now, but I suspect the 1/2 line from the pump to carb is what was causing your problems in the first place.
The fuel was slowing down in a 1/2 line in a hot engine compartment right before it got to the carb and soaking up heat.
An insulated 3/8 line from the pump to carb would have likely solved the problem.
I live in AZ and the 3/8 feed and returns with an electric pump solved it for me, and I don't have a regulator in the system.
When I put the system together I put a fuel pressure gauge in the feed right at the carb and a restricting orifice in the return line to give the 6lbs pressure on the feed line.
What the carb can't use returns to the tank.

But hey, you wanted a new system anyway.:D