Doesn't really matter what the donor engine was marked. If it has an EGR valve, it's not an "X" engine. If it's a '96, it's not an "X" engine. It might have the upgraded injector assembly like the "X" has, but that doesn't make it an "X" engine, (it still has the EGR valve). The first year for the "X" engine was 2002. It was installed in C/K, L/M platform. The first year it was used in G, S/T platforms was 2003.

Most of the information comes directly from GM factory publications. It doesn't get any more accurate than that. There is also some [limited] factory information available online. VIN decoders and RPO codes come in real handy too.

I have not personally done a swap from "W" to "X" or vice versa, nor will I in the future. I know what's involved, and it's not worth the hassle of re-engineering everything.

 

I had no intention of re-engineering anything either! The yard assured me it would bolt right in. But I guess if what your saying is true it's a w anyway... Still, if the engine is getting the right fuel, spark and air it should at least start, shouldn't it? When I try to start it the engine cranks over fine and you can hear the exhaust going *put put put* like it's trying to fire but maybe is out of time? If this was the case would it start up for at least a few seconds on starter fluid because it wouldn't? My father in laws suggestion (he's worked quite a bit on blazers) was to swap the spider. I still have the old engine to pull parts from. I've swapped the ignition module, pickup in the distributor, rotor and cap, plugs and wires... Basically all your ignition components. I know I'm getting fuel in the cylinder but whether it's the right amount or not I don't know. I might have to go rent that tool to test it. Will the rent a compression tester? And if so, can a novice accuracy check it?

 

The S10 had a lower output version of the 4.3L that was a VIN X motor back in '96. I believe it was RPO code LF6 rather than the VIN W RPO code L35. There is a lot of speculation about the differences between the two engines with many suspecting that it was in programming only due to the output differing by only 10hp and 10ftlbs, but I suspect that there is a difference between the cam profiles used in the two engines which likely changes the power curve. Otherwise there wouldn't be a need to have a completely different VIN & RPO code between the two engines as the VIN already details the vehicle & drivetrain configurations separately which could be used to define programming.

Regardless, if the engine came from a '96, it will bolt right in.

If it did come from a newer vehicle with the LU3 engine, then at most you would have to swap over the lower intake manifold to retain the EGR system and drill/tap the knock sensor mount for 1/4" NPT threads to allow the use of the older, single wire knock sensor.

 

This is a lot more in line with the research I've done. The engine did bolt right in with a oil pan, pump, and remote oil line swap because the donor was from a '96 2wd s10, vin x. Do you think the PCM needs to be swapped even if the programming is somewhat different? According to newgmparts. Com the 96 PCM is the same in the s10 and blazer, and in '98 it's the same PCM in the s10 and blazer, however the PCM is differnt from '96-'98... If the '96 s10 PCM will run a blazer engine wouldn't it run a '98 blazer engine? If not then in order to take a '96 blazer engine and put in a '98 blazer you would have to swap the PCM too, correct?