I also chose the RCI fuel tank. 15 gal. 15w x 36l x 9h. This fuel cell has (1) fuel supply fitting, (1) fuel return fitting, (1) tank vent fitting, and the fuel filler. It also came with my choice of fuel gauge tank unit. I really didn't put much thought into the location until push came to shove. I mounted it between the Cadillac engine and the firewall. Due to my tube chassis in the rear, I had to relocate the filler and the fuel return fitting. I am finding that there is a lot of re-engineering that goes into these builds.
Jim