1966 GMC carryall side windows

[DRUMWAGON]

I started retrofitting this 66 GMC carry-all in the spring. The rig has been sitting for almost 20 years and the engine and drive train where completely seized up. I had a wrecked 89 suburban and it made good since to swap the 66 body onto the 89 chassis. When I removed the sliding side widows, the frame assemblies completely fell apart with rust and cannot be repaired. I have pop-riveted some sheet metal in temporarily but would like to put the sliding windows back in. (glass is good) If anyone has any suggestions or knows where I can find some frames please let me know. Thanks! –Wayne-