If you're planning on reconditioning the frame on a C2 or C3 here's something to check. I found this a on what looked like a great replacement frame for my '67 that I'm fixing up. After getting this frame home I took it all apart to start the process of getting all the surface rust off prior to painting. There were no noticeable issues until I disassembled the front suspension and started wire brushing off the surface rust. The following pic is the underside of the frame where the front coil spring tower ties in with the frame and there were cracks on both sides in the same area.
I got a welder to come and look at it and right away he recognized it as a Corvette frame. He said this isn't uncommon if it had a big block. My '67 is a small block but this rolling frame has several things that indicate it probably was a big block. The differential stamping (AT 11 21 66 on btm of diff. Indicates a 427 3:08 posi.), and also where the metal fuel line ends near the engine, there's a different bend there from a small block. Anyway we got the frame to the welding shop and he took care of it. Just a heads up!
I got a welder to come and look at it and right away he recognized it as a Corvette frame. He said this isn't uncommon if it had a big block. My '67 is a small block but this rolling frame has several things that indicate it probably was a big block. The differential stamping (AT 11 21 66 on btm of diff. Indicates a 427 3:08 posi.), and also where the metal fuel line ends near the engine, there's a different bend there from a small block. Anyway we got the frame to the welding shop and he took care of it. Just a heads up!