I'm not sure of the design of the intake manifold, but I would strongly recommend against running a 3-bar sensor on a normally aspirated engine. You will lose 2/3 of the VE table resolution. You would not need to bolt in the MAP sensor if you are not running boost.

The later model PCM's would include the 1999-2002 512 meg PCM. 16238212, 9354896, 12200411 are all 512 meg PCM's. https://www.lsenginediy.com/comparin...i-controllers/ has some good descriptions of various GM PCM/ECM's. If you are interested in updating your vehicle to the 1999 up PCM you can email me or PM me.
Al