C3 Frame Repair questions

I'm getting started on the frame repairs and upgrades on my 78. The first task is to replace the rusted section at the typical location – drivers side at the rear kick-up. The frame is straight and square, and I'm pretty clear on the bracing that needs to be installed prior to cutting into anything.

http://i221.photobucket.com/albums/dd137/CTVETTE78/78 Corvette/Frame008.jpg

I have the kit to replace the section from the transmission cross member back; the kit includes a sleeve to strengthen the joint where the frame is sectioned. What is the best way to install the sleeve since the mig welder tip can't reach in far enough to weld the sleeve to the inside of the frame? I was considering drilling a few holes in frame in the area of the sleeve and plug welding it, but I want to inquire with those that have performed this job already to see if there is a better way. I've seen quite a few write-ups out by folks that have done this job, but none of these address this question.

Also, I have a known weak spot in the area of the #2 body mount, another typical location. There is no pre-fab replacement metal available for this area, so what have others done here? This area appears to have some compound curves to it so bending up a single replacement piece looks like it would be pretty difficult.

I appreciate any and all ideas or suggestions.

There's a local guy here who has a couple C3 frames hanging in his shop. He has all kinds of odds and ends for all Corvettes.

If you want his number, maybe a new frame is better than a repair.

These things are kept INSIDE so they are pristine.

After you cut off the bad part you can simply make your own sleeve, all it needs to be is a piece that you can weld on the inside of the remaining frame section so you can slide the new pieces over it. The easiest way to attach this is by drilling holes in the old section, sliding the sleeve in and then doing some plug welds. Slide the new section over after drilling holes there too and do some plug welds on that side. Then finally weld up the seam.

What damage do you have at the #2 pos ? Rust on the top from water retention by that stock foam piece crammed between frame and body? The only way to fix it is to cut out the cancer and fabricate replacement pieces yourself.

Thanks TT. I figured that plug welding the sleeve was probably the best way; I wanted to see if I may have been forgetting something. The sleeve is furnished with the replacement frame pieces so I don't even have to fabricate that part myself. What could be easier, right?

The problem at #2 is also rust. I found a lot of scale inside the frame at this point and after blasting, a hole adjacent to the body mount was evident. I'm planning to remove the mount and replace the metal in that area as required. It will be a bit more challenging to get the shape correct here.

Aside from these two spots, this frame is really in pretty good shape overall, considering that it came from a northern car.

I'll post some pictures of my results.