[dsraven]

it's Dennis actually, but I have been called worse, lol.
the Canadian frames all have Gm stock corvette stuff. I actually toured their shop a couple of years back and seen first hand. rebuilt on site, it's all the guy does so he should know his stuff. their frames also have the fuel and brake lines (and battery I think) hidden inside with bulkhead connectors for a nice clean look. the frames are cut from sheet with tabs left as spacers for a full depth weld. seemed like excellent quality to me.
the firewall is an easy thing to build from16ga sheet stock. if you are fabricator at all you could save a bunch. I would recommend redoing the hinges and getting the doors and gaps like you want them. then cross brace everything so the cab stays square etc. THEN cut out the firewall and do the replacement. same if you have door pillars to do etc.
here are a few pics of my homemade firewall. pardon the mess. ensure you make templates of the hinge bolt hole locations before you start, with reference drill or center punch marks. some guys have also used a steel wheelbarrow tub for a firewall because it is already shaped and round