Hi Guys, I’m going to have to ask for your patience on this one because I’m 90% positive this could be answered with a search, it’s just that I’m not exactly positive what keywords to search for or even what this thing is "officially" called, so let me explain: I’ve got a comet that is getting converted to full drag car that I want as light as possible. It's caged and I stripped the interior but behind the rear seat is a brace or a bulkhead or… I don’t know what it’s called really, but it’s the metal bracing complex behind the rear seat. So it’s the cross pieces behind the seat, and the back tray that held the old 6x9 speakers, an interior colored finish panel that goes right to the rear window and the under-framing that goes to the trunk hinges and the bracing of those hinges to the wheel tubs. Some parts looked like they bolted in at one time because there are factory looking holes through parts and corresponding holes in the body panels. There are three or four of these per side all empty of bolts but the pieces won’t move. There are some welds that I suspect are not factory even though they are under paint because there have huge weld whiskers from shoddy MIGing sticking out of them and I know it had a rear quarter replaced in the 80s. That’s the situation, now what I want to do is just death-wheel everything out of there and pin the trunk to save weight, however it sure looks like the part of the frame that holds the trunk hinges becomes something important when it goes into the trunk. It seems to be connected to (or rather it seems to “become”) the portion of the body that is between the rear window and the trunk. I used to own a drag comet that had the trunk dzus fastened on but I completely forget how much of that bracing was gone since I bought the car mostly complete and that work was all done. So, I know it can be done, I just don’t know if I should go all caveman on this and rip out everything and hope enough is left to not have a floppy body panel between the trunk and window or if I should selectively keep some bracing. So I figured I’d appeal to the community here to find out what others have experienced. How much of this can safely go?
The holes are locating holes I believe and they are welded (poorly) from the factory. Mine were actually missing when I removed the seat, you could see where it may have been welded and there was even some spray on seam sealer with the outline of the brace. I think you would lose some structural rigidity if you removed it and I don't think you would see much weight savings.
The braces behind the seat are just that. To brace the back seat and the upper fenders. But the welds they use, they might as well not be there. The rear area behind the seat is cosmetic. You can remove it also. BUT, if you have a battery and/or gas tank in the trunk you have to have a metal barrier to enclose the trunk from the pass compartment. Several ways to reduce weight. Mostly in the front is where you need to take it off to balance out the car's weight front/rear ratio. Front sway bar, (useless when drag racing), coil over spring system, Mustang tubar control arms, light weight rims, (steel weight twice what a Weld Draglite weighs. Get rid of the radio, heater, door panels, carpet, etc. Gut the interior in other words. Then you can look at fiberglass front fenders and hood if they make them, plus the inner bracing and shielding. Even skinny front tires reduces weight. Change the factory front seat, (only need one) to fiberglass racing ones. You'll loose 20# right there. If you have the "5" MPH bumpers, get earlier ones or fiberglass also.
Yours is done far better then Ford even did. Due to more welds and braces it along with a roll cage, probably frame stiffeners also, it's a far more solid platform. When you modify the Mav/Comet for drag racing, just frame stiffeners and roll cage, even just a 4 point, makes the uni-body much more solid. What I did to my Mav was also weld up areas in the front suspension and add a A-arm stiffener in the lower shock/frame support. I also notched the shock towers and used beefier metal plates to reenforce them also. It makes spark plug changes so much easier. I also reenforced the cross brace.
