This is a line vector of what I am thinking about doing. I would remove the chassis engineering and get a 2x4 chassis stock and cut a portion of the top out and slip it over the existing factory rails, and tie it into the back of the rear cross member with transmission loop in it, then attach the back half kit (Eliminator II) It would also give me strong points to mount flat plate to accept the roll cage. Thoughts, Idea's, critics? note -- grey box's are torque box's. Backhalf kit I am buying myself for xmas
All depends on the track width of the front suspension your using, and how wide of tires you want to put in the rear. This might give you some ideas: http://www.schwartzperformance.com/1964-1973-mustang-chassis-full-frame/
The front frame rails would stay the same, and I would just slip chassis tube over it, and weld in place, and run it straight back to the backhalf. The outter portion of the chassis would tie into the torque box, and taper into the new frame rails. I could probably do the entire chassis for the cost of the back half chassis kit (350$) and maybe 50-75$ for the remaining stock (family owns machining company and get metal for pennys 52 3/4" Out side to outside (outside frame rail that would attach to the rockers 50 1/2" inside to inside (outside frame rail) 26 1/2" inside to inside (exsisting width frame rails straight back to the backhalf kit) 31 1/8" outside to outside (inner frame rails (exsisting frame)) The rear back half chassis would more than likely be 30" outside to outside (28" inside to inside) and according to the sheet below the entire body with would give me roughly (outside exsisting frame is 41" wide for the rear end) would give me possibly 22" of tire space in the rear if I went with a 30 back half outside to outside frame width right?
That is similar to what I did when I built my 4 link cross member. I cut the very back of both front frame rails out that go under the floor, then took 2 lengths of 1 3/4 steel tubing and pushed them up inside of the rails almost to the firewall. Then I took a 1 3/4 inch hole saw to the front of my new rear cross member and pulled the 2 pieces of round tubing back and into those holes. I still have to do some bench welding on the rear cross member but once it gets installed for the last time everything will get welded in solid. I also drilled holes in the bottom of both original frame rails so I can plug weld the frame to the round tubing. You see my round tubing goes through and sits above the rear floors but your 2x4 is certainly going to do that too. I think 2x4 is way too large and overkill since you also have a cage to tie it all into. 2x3 might certainly work out cleaner for you but you might have to slip it over the front frame rails on the 3 inch width because the stock frame rails are exact or just slightly larger on the outside dimension than 2 inches - larger than the ID of a 2 inch side of a piece of 2x4 boxed tubing
exactly. after going out to the car and taking a few measurements I thought the same thing, 2x4 would be over kill, and 2x3 would be more reasonable. Issue I would have is getting the OD of the existing frame rail is 2 1/8" so cut that out of the top of the 2x3 (3" being top) and it would slip on and be smooth all the way back. Then off set the back half kit. Mini tubing the car will give me roughly 14" from outside frame rail to the inner lip of the wheel well. If I pushed the back half kit in another 4-6" that would give me a comfortable 15-16/17" of tire space would I believe be sufficient and do like a 10" tire in the front. Good staggered/rake look. Also, I would end up doing a complete new floor pan, and would more than likely raise the entire floor about 2 - 2 1/2" higher than stock. with a tin kit from chassis alston Kit is 149.99$ $209.99 trans tunnel $150 for the set $300 for kit Could more than likely re-floor entire car, new chassis, and back half kit for about 800$
How I came to know that dimension was I already had 2 lengths of 2x2 laying around, from my stock car building days, that would have worked if not for that weird dimension of the OD of the stock rail. That was when I grabbed for the 1 3/4 round tubing and it went right inside Instant "new plan"
Which would be best, square or round? Pros and cons of both sides, I understand that -- but to keep it light, and sound im thinkin round? and do 2x3 on the outside to stiffen it up?
I love these types of conversations! IMO, you'd have to compare apples to apples for wall thickness to really equate the differences between the two. And I have to say.. the more I see Bob's design work the more I really like his car and respect the amount of engineering he's put into it. I myself plan on doing the same thing but will be using only slightly thicker guage square rail close to the same size as the rear rail. I will however be continuing the offset architecture between the front and rear rails.. with the rear end of the new rail tying into the side of the existing rear rail/floorbaord, rather than trying to mate up with it straight on. From there I'll fully box the rockers to the main rail to tie it all together. And since I'll eventually be road racing my car.. well, moreso than the way I typically drive on public streets and highways as it is.. and would be much more concerned about torsional stability vs a straight line car.. I'll also incorporate a double firewall.. some floor pan cross bracing.. and maybe even go so far as to utilize structural foam wherever possible. Using foam enables the use of thinner guage sheetmetal/square tubing without sacrificing one bit of strength for that weight tradeoff. After being fully seam welded.. the front torque boxes and existing rails can also be loaded up with structural foam as well. So, IMO.. if you plan on running a square tube rear backhalf and tying into the existing front rails?.. I'd probably stick with square tubing of only slightly thicker design than the original front rails and work on adding a few gussets here and there along the way. Sure won't be what anyone would call "weak and flimsy" and still maintain a lighter design in the process.
Im doin it -- screw it Got the floor sectioned it out, and removing all the damn spot welds. I cannot get the right angle with the spot weld remover because of the existing floor in the car now -- so I got it butt cut to where its flat, and took a disc grinder and grinding it down slowly, and individually. Pain in my arse! Ordered up the metal for the firewall to get cut out then I will pop some cleco's in to hold it and go from there Need to get everything cleaned up, measured and order some 2x3 .083 chassis tube, and begin the mock up process.
Kudo's to you! Sure wish I could just push other projects out of my way to start cutting on mine too. Patience can be tough to maintain sometimes when I see progress like yours. But.. drivetrain comes first so me and my 2 boys can cruise around a bit next summer in semi-sleeper stock form before I start cutting everything up. I also figure it will be nice for evryones memory banks and the old picture albums later on too if we all enjoy square one rather than jumping right to square 5. Especially since I tend to go massively overboard as I progress through my own personal projects("sigh.. may as well do that too while I have it all apart and exposed").. which inevitabely ends up taking twice as long and costing 3 times more than first anticipated. But.. such is life in the car hobby, I guess. Plus.. being power crazed only makes things worse. lol So, I have a couple of quick questions. How much weight do you anticipate adding to the structure of this car with chassis reinforcements and cage? 150'ish or so? And what about the final interior layout? Full gut?.. or partial? BTW.. thanks so much for all the pic's as they'll surely be appreciated when I and others start cutting into the floorboards of these cars. :Handshake
I don't plan on adding very much weight, if anything I'll loose some weight. I am thinking of doing alumina floor plan wit pop rivets and seam sealer. That will give me the abilityto make changes if needed down the road and save on some weight. The tube i am putting into the car isn't very heavy, it's. 083 which is about 2.3 millimeters thick or 16th of a inch, but will make a huge difference in everything. I will have full interior in the car from rear of drivers seat forwards. Everything else will be sheet metal and maybe a carpet kit to keep things nice. It will be a very nice Street show car iI am hoping.
Aluminum floors sound good but all of those pop rivets never look good hanging down from underneath the car. Maybe you could plan your rivet pattern in a row very near cross members and then make a bent cover to hide them just to give the underside a more clean look
It`s a good thing you`re not drag racing,tubing that thin would not be allowed in the NHRA or the IHRA.
It all depends on how fast the car is and I've certianly seen many hybrid arrangements like this through the years. Not on dedicated 9 and low 10 second "drag only" cars... but upwards from there. So, for a roll cage?.. no. But when used for supplemental chassis bracing in a unibody car?.. sure it would. Not like he's losing all the unibody and going to a full tube setup here.
