Okay, the center tunnel is figured out. As shown, the two lower holes support the coolant lines. The top hole is for the bleed lines (which may be fairly large OD if silicon hose is used.) The large tube at the top serves several purposes: it provides a smooth surface for the center tunnel (I don’t like resting my elbow on square corners,) it serves as a through-passage for shifter cables, clutch line, brake lines, and electrical. If that all doesn’t fit they can run below (and yes, there will be gaskets in each hole to prevent wear).
The large top tube also provides a physical support for the shifter assembly and possibly the e-brake. The only thing I wonder about is what happens with that tube in a wreck. Worst-case it gets shoved through the firewall, punctures the fuel tank, and creates a really impressive fireball. For that to happen, the front of the car has to get crushed about 3 ft plus another foot into the passenger compartment for it to reach the firewall – which seems pretty unlikely. However, I’ll probably drill 1.5″ holes along the bottom of the tube to make sure it buckles instead, and the holes will also double as passageways for cables or hoses to pass between the upper and lower cable-ways.
Note sure what to do next. The steering parts are on the way so that can’t happen until they show up. Doing some panels would be a nice change of pace, though I think it would be best to fully weld the chassis first (so it assumes its final shape due to whatever heat-warpage happens). No point drilling rivet holes only to have them shift during final welding. Maybe it’s time to add the rest of the tubes at the rear, around the suspension area and diffuser, then final weld the chassis… The only catch is that I haven’t made up my mind how I want to handle the body work around the rear, nevermind the side vents. Since that’ll use smaller tubing it shouldn’t affect the overall chassis. Oh, and there’s the pedal assembly mount to finish in order to get rid of all the clamps and wood!