I agree on the fuel injection swap if the donor vehicle is available. I have an 87 and its fuel injected, same engine and starts up every time. Its no power maker, its a 350 and I wont be doing any exhaust or power adders. Its not very advanced but its reliable.
The valve seals on those engines are known to go bad, $400-500 to get it done by a mechanic. Tell him to check them. Otherwise its a good ol reliable 350.
I also agree do the $450 engine if you are buying a house. Another thing to consider is buy the house and get the Vortec after your financing is done. Credit card it and pay it off over a year. They were $2000 shipped awhile back.
You will get your money back when you sell it if you do things like fuel injection, vortec, 700r4, etc.
To answer your question though, coming out of a suburban its a 350.
That motor is reliable, my dad got 300k out of an 89 before he parked it to only use as a farm truck. Still ran fine. Valve seals in it started going bad. Traded it off for some work and saw it around for quite some time.