I currently have a 2001 chevy blazer 4wd, and I have an opportunity to get a 1996 chavy blazer 4wd to use for parts. I am wondering if the parts are interchangeable, or at least enough that will make it worth getting?

 

I believe the 96 is a first gen and second gen started in 98, so I wouldn't imagine to much would be interchangeable. If I am wrong someone else will correct me.

 

In Canada at least, 95 was the crossover year with the 2nd gen body style, but had the older style Vortec engine and OBD 1.5. 96 and 97 are the 2nd gen body style with the same interior as the 95, and they share a lot of suspension and drivetrain parts with the late 1st gen Blazers. Many parts will not interchange with the 98-2005 trucks. For example, on the front end, the brakes, hubs, knuckles, CV axles (on a 4x4), and front differential are all different from a 96/97 vs the 98+ trucks. The interior is different as well, but I believe the seats will bolt up if you need to swap seats.

My experience is when I swapped the axles on my 96 Blazer to get 3.73 gears, with ones from a 2001 truck I had to also swap the CV axles because the older trucks use a bolt-on flange style CV, and the newer trucks use a plug-in splined axle.

 

@El_Beautor ist correct. Following information may narrow down the interchangeability.

1992 is the 1st gen which saw the new 4L60E transmission with electronic control
1994 is the last 1st gen (square and square hood)
1995 is the transition year where you can find all weird setups under the hood. (round and rounded hood)
this means that despite the new body you can find early production VIN's with old engine/transmission combos.
You can find weird electronics (ECU) with and without OBDII.
1996 is a 2nd gen and should have proper OBDII and consistent 2nd gen engine/transmission.
1998 saw various modifications to the engine and other parts, including body style updates.

About interchanging parts it would depend on what you intend to swap. Many mechanical parts interchange even between 1st and 2nd gen.
Engines are another story. While some engine internals are interchangeable some are not. Main differences are in the fuel injection.

Without being correct looking up specific parts in auto-parts catalogs and checking which vehicles they fit can be a good indicator.

 

My locak GM Parts department told me I could swap parts from a 1995 S10 up to a 2001, especially engine etc, they said 2002 changed.