most of this info comes from 60V6.

all 2.8 engines in W-bodies used aluminum heads, MPFI, flat tappet lifters, stamped steel 1.5:1 rockers and DIS. they are all Generation 2 60V6 engines.
they employ 28cc heart shaped(fast-burn) combustion chambers.
28cc dished pistons are also used.
both the intake and exhaust valves are splayed.
the engine is internally balanced.
compression ratio is 8.9:1
pistons are intended to weigh 510grams.
2.8 motors are rated for 130HP/160TQ
1988 came with a rather faulty MAF system that got a recall issued that disabled the MAF and used speed-density for fueling. any broadcast code other than ASWH, ATRA, ASWJ, ASWL or ASWK still uses the MAF.