Will a turbo 400 transmission fit into 1997 Chevy silverado 4x4 with 5.7?

No, a TH400 (Turbo Hydramatic 400) transmission will not directly fit into a 1997 Chevy Silverado 4x4 with a 5.7L engine. The 1997 Silverado likely came with a 4L60E (or possibly a 4L80E depending on the specific configuration) which is an electronically controlled automatic transmission. The TH400 is a much older, mechanically controlled unit with a different bolt pattern, output shaft, and overall dimensions. It would require significant and extensive modifications to the vehicle's transmission tunnel, driveshaft, and possibly even the engine mounts to even attempt to install it, and it still wouldn't be a reliable solution. The computer system in your Silverado is also designed to work with the 4L60E/4L80E and wouldn't be compatible with the TH400.