Short Answer: No, it is not a direct swap.

Long Answer: In terms of their physical make up, they are pretty damn close to each other and should be able to be swapped. The problem: incompatibility in the form of the programming. You may be able to have the dealer reprogram it to your VIN though.

 

i heard from a few people u can thats y im askin

 

Programming will be different. One easy difference is the 96 truck has 4 O2 sensors and the 98+ have only 3. The PCM will be looking for the pre-cat O2 sensor that the 96 has and will not see it because your 98 has no such sensor.

At the very least you would have to get the PCM reprogrammed for your truck, most likely by a dealer to the tune of at least one shop hour. I believe that another member had his PCM reprogrammed by the dealer recently costing around $100 and that was just to add RKE (remote keyless entry).

 

could i pick up a pcm from any 98-04 blazer and send it to one of the custom tuning places and it would work in my 2000 blazer?

 

I rather doubt it. They'll change fuel curves, timing curves, etc., things affecting performance. But I rather doubt they can add production options. Examples: my blazer doesn't have fog lamps and I'd like to add 'em (factory that is). A bit of wiring, a headlight switch, it seems simple..... except I'd have to have the dealer add the option to my computer. Ditto for the tow/haul option, the wiring is all there, just add a push button switch, but the RPO needs to be added to the computer (this I tried) <grin>.