Re: Rear Quarters Installation Advice
You should be ok but I would weld a couple of pieces of square tube from the end of the frame rails to the floor to give some support at the rear.
I think you should be alright. The biggest thing I believe is that you don't want the car to move. I did skins on my car with it on stands and it came out fine. Just make sure you take your time.
You'll be fine with the car supported as you have it. I replaced the quarters on mine while on a rotisserie with no ill effects. Having the doors in place was a good move. When you receive the parts verify the wheel house fits the quarter properly. If you're using wheel well moldings verify they fit properly. All prior to installation. You will quite likely need to trim the sail panel edge to fit inside the drip rail. The manufactures don't care about edge trims and finish. If the drip rails are still on the car you will probably need to bend them down a bit to help when fitting the quarters. Take your time and be patient. Use lots of clamps and only tack weld when you feel you are close. There are a lot of seems with the quarters. Be prepared to install and remove the quarters a number of times. Like 20 or more.
Added: Supporting as described requires the rockers to be in good shape.
Do you have a spot you can do all of the work at ?.
On my 74 Nova hatchback I replaced both full quarters, both rear outer wheel housings and the taillight panel and I knew before I even started cutting things off, the remaining structure could move and it would be more flimsy than what it would be when all together (not to mention the cars were build with jigs which some do construct) so what I did was pick a spot in the garage and took some square steel 1/2" tubing I had laying around and then measured from some points like below the rear taillight/bumper area, from the front spring eye area, at the base of the firewall, and at the spot where the rear axle stop bumpers were at to the garage floor and then cleaned the metal to where I could tack weld these supports vertically to the underside of the car. I used a framing square to try and get the tubes as plumb as I could.
I then had these 8 supports under the car and then placed jack stands around the 4 corners of the car for additional support but had them to where they were in place and doing a little to stabilize the shell but the main support was from the vertical tubes.
I then started drilling out and cutting away the quarters and wheel housings and guess what, one or two of the supports lifted off of the ground. Once I got the metal off that was to be replaced, I placed weights above the lifted supports to twist the remaining structure to the point it was originally.
Eventually I got to the point of getting all of the new metal back on the car and all the supports were in contact with the garage floor so I knew what I attached to on the old structure was where it was at before.
I then took a cutoff wheel to cut the tack welds loose and the tubes to remove them and then removed whatever weld was left from adding these temporary supports to the car.
At one point I did have to move the shell so I marked the floor exactly where the supports made contact on the concrete,moved the car and when returning it, placed it right back where it was before to continue on with the work.
If you look how things were originally done, the outer wheel housings were spot welded to the quarters and then the quarters put on and then the outer wheel housing got spot welded to the inners (as well as in other spots). I positioned my outers in place using self tap screws to hold them in place to see how well the quarters fot by putting them on with a test fit and then had to take the quarters off, shift the outers one way or another and then tried the quarter on once again. I had to do this numerous times and then once I was happy with the fit with the outers and quarters screwed and clamped down I then went further with my mockup by trial fitting the hatch lid to see how it also fit before ANY welding got done.
Once I was happy with the TOTAL fit I then blew it apart down to the first part that needed to be welded in and then mocked the car back up together fully once again just to check things then if things went right, blew it apart to continue adding panel and panel to the car and eventually got it all together with minimal fit issues on my hatchlid gaps.
Keep in mind all of the parts whether NOS, off of a donor car, reproduction, or whatever are all just a tad different in tolerances and by addressing things and correcting issues by mocking the whole works up, the better the end results should be.
I had never done full quarters, along with outer wheel housings and a taillight panel all at one time but it made me feel real good by taking my time and getting it right especially when a pro bodyman came by to check out my work and told me I did a fantastic, super professional job.
Thanks gents! It's good to hear your opinions and approach to this task.