The fuel and brake lines are from Inline Tube. I modified the master lines because they only had ones for power brakes, I have manual. Of course, the rear axle lines would never have worked so I made those myself. The Inline ones are for an f-body length 8 1/4" rear. I almost made all the lines from scratch but for the cost of prebent with the spiral armor spring and the correct fittings, etc, it wasn't worth the trouble. If I remember right, the fuel and brake lines together were only about $160. Used Inline Tube trans cooler lines as well and ordered ones to fit a big block '73 Roadrunner. Fit was perfect, only mod was at the radiator. The RR uses threaded fittings, Aspen uses flexible hose connections at the cooler. I originally got the repop 360 Aspen trans lines from them and there was no way they were going to work with a big block.
The subframe connectors are just standard 2"x 2" square tubing welded to the stock subframe rails and channeled through the rear footwell area with the floor welded to them. With the carpet, you never know they're there. They've been on the car for almost 30 years, just after I originally did a bog block swap. It was obvious after driving the car right away that connectors weren't an option, they were mandatory.
