The 350 TBI in my Cadillac has 105k miles on it(yeah, they put a Chevy truck motor in them from 90-92) It runs pretty good, but could run better. Doesn't use any oil or blow any smoke though.

I plan to change:
Spark plugs
Spark plug wires
Distributor cap
PCV valve
Air Filter
Seafoam treatment(before I change plugs)

I've already done the following:
Oil Change
Coolant flush(three times, it was really nasty)
Transmission service

Anything else you recommend I do while I'm at it??? This is the first car I've owned with a SBC.

 

Besides the cap you need a rotor, but it looks like you are covering all your basis, should run a bit better. Use a rechargable air filter if possible. And use some carb cleaner to clean as much of the black carbon deposit possible from the throttle body and blades inside.

A old toothbrush works well.