[WSSix]

You need to check the bird cage and frame closely for rust. The frame isn't that huge of a deal on a custom build in all honesty. Sure replacements aren't terribly cheap but there are a number of options and if you compare a built frame to building a stock frame, the costs are similar with the built frame being a far superior design.

The bird cage is a huge deal as it requires the body to be broken off the cage in order to get at the cage itself. At least this is the correct way to do it.

If you're building a custom vette, the 64 is just fine to use as its downsides will be replaced. The biggest downside is the four wheel drum brakes.