Yep, that's a squarebody. The front crossmember is an easy swap. IIRC, you have to drill 1 or 2 holes, but once you get them both off, you'll see what you need to do by comparing both frames.
If the Suburban has a mechanical speedo, it should just be plug and play to make the speedo work. If your '68 has factory gauges, the oil pressure gauge is mechanical so it will work anyway. All you'll need is the '68 sending unit in the newer for temp gauge to work. You will need a kit to make the lockup converter work in the Suburban's transmission, if it is a 700R-4, unless you are putting the computer and wiring out of the Suburban in the '68.
If the engine in Suburban is EFI, and you want you run that, somebody else will have to help you on that, because I don't do fuel injection. Unless it's a diesel!
