Can You Swap 4.2 & tranny into a 97 blazer

 

If you're talking about the 4.2L I6 engine from the newer Trailblazer/Envoy/Rainier/etc, then you're in for a LOT of work if you attempt to shoehorn that engine into an S-series engine bay. The Inline 4.2L 6-cylinder engine is LONG and TALL. Nearly 3" taller than a v6/v8 and 6" longer than the 4.3L Vortec V6. Some of the height can be cut down by making a custom oil pan, but the length is the real problem. It is longer than a V8 making it easier to drop in a 350 (or other SBC/LS engine) than the Vortec 4.2L I6 engine.