Started out just planning on replacing the body bushings. One thing lead to another and before you now it the frame is out from under the car, and off to the sand blaster. If you have a convertible or real GS frame you do not need to do this. If you have a Skylark the frame needs help. ABC performance makes a frame boxing kit for $200. Gives you 4 laser cut plates to help beef up the frame. This picture shows the back section of the frame tacked in. That was easy to do. This part of the frame is usually in good shape and it just takes a few tweaks to get it to fit.
The middle section of the frame is a different story. After 46 years of abuse the bottom of the frame is no longer in the same shape as it was from the factory. Most of these are all bent up and so was mine. I c clamped a length of 2X3 box channel along the bottom. Then took some more c clamps and applied pressure. Then tack welded along the bottom. Next step is to use an air hammer to convince the metal it wants to stay where I want it.
Found a better way to do this on the second side. Here is what the frame looked like to start with. Amazing how out of shape that bottom gets.
I used the handy 2X3 chunk of box tube along the bottom of the frame. There are some protrusions on the bottom of the frame to avoid or it will set too low. Use some quick clamps to hold it in place. Cut out the chunk of metal that connect top and bottom rails in the center of the frame. I just lined up the edge of the top rail and used that as a guide. Same at the bottom. Next use two c clamps on each side of the area the center body mount is. Use the c clamps to draw the bottom rail down to the 2x3. Next step is to make a brace from a piece of 1/8 flat stock. I used 2" wide stock. The brace is going to hold open the space on each side of the body bushing hole. Make sure you leave enough room for bushing. Should be a rectangle about 2x2.75. Try to make it a tight fit. Then weld it in. Should look like the picture. Do the same thing on the other side of the body mount hole. Then you can start working with the C clamps from the center out.
Work the C clamps to each end flattening the bottom of the rail. The problem is that releasing the C clamp will let the deformed part of the rail to pop back up. So on each side I put in two more braces. As you work to the ends and have a flat spot between clamps work in a brace. Only trick here is to place the bottom of the brace about 1/4 inch from the edge of the frame rail so you have room to weld the bottom then the top.
Now it just a case of lining up the the boxing plate and tack welding it into place. C clamp work great for this too. My next step will be to take it to someone that is a better welder than me (trained monkey in my case) to do the finish welding.
Guess I've always gotten lucky, all my frames are straight underneath. I have a 71 Skylark convertible and the rear frame rails behind the rear tires was not boxed in at all. I had to buy a drop in piece from ABC performance to box this part in. Turned out nice but I don't think this part of the frame gets put under much stress unless rear ended.
Tony said that the rear is important because of the body mounts. It all has to do with tying the whole system together. Do the wagons have the same frame bracing as the convertibles and GS's?
I went a little farther with this ladder structure tying the lower rear control arms to the front frame section with the struts stopping frame from racking.Looks cool, no body mods and barely visible from the side.
I thought about doing something like that. In the end did not feel it necessary for my goals. Did you ever upgrade the front end? The stock geometry leaves a lot to be desired. Will have pictures of frame all put back together soon.
No front end work yet just basic stuff , Firebird sway bar and fast steering box. Money is tight so looking at B or F spindles with larger brakes. Waiting for the right donor to drop in my lap. Upper arms would be nice but pricey. I didnt really have a solid plan when I started, I only wished I had modified the frame for wider tires in the rear. I saw this at the powder coaters the other day. Looks like it would have be pretty easy.
ABC has a nice kit for that too. My car needs the extra tire but more traction equals more broken parts. For me the tires are the fuse. On top of that what is the 275 drag radial record? Way faster than I will ever go. I run B body spindles and Global West uppers. Someday will put on the D52 replacement calipers but things work good right now. With the B spindles and Global West springs it was a bit too low in the front and have to run a half inch spacer to get things good for the street. I have heard that the B spindles will cause excessive bump steer but I don't see it. Part of that may be I do not run super low profile tires. 15 inch wheels and 235/50's in the front makes for a good street setup.
Not sure about how much planning went into this. Put it on wheels today. Then looked in one of the parts boxes and saw the brake calipers. Would have missed them when I run the brake lines. ou:
I just bought the kit from ABC. Are the pieces suppose to fit inside the frame or just set against it?