While impatiently waiting to get heads back on the shortblock couple questions.
Is the carb ready to go back on? And what did you end up using for choke pull-off, sec rods and hanger. If i remember you pull the carb apart and threw some gaskets in and some Ruggles parts. What sec rods and hanger are in the carb now. Carb needs to be done and ready to bolt on.
Did you check out the dist, connections, internal wires, and endplay. Most of those Delco dist had to much endplay, maybe .030", shimming the gear drive can reduce that to .010-.012". Setting endplay can reduce ignition timing change, wear on the rotating parts. Just a common adjustment on Delco dist, endplay check.
Torque converter? First flex plates can be a problem. Double check for any cracks at the mounting flange, Also inspect the ring gear. A new SFI flex plate isn't that expensive.
Are you installing a higher stall converter? I believe the original stall was 2100, upping that to high 20s would be a plus without any real negatives. Just help the little mouse get out of the hole a little quicker.
Did you replace the front and rear crank seals? The one piece on those engines is actually a decent setup, much better than the old 2 piece. Changing rear seal is easy and insurance. Timing cover crank seal can be seapers even when new, also check the new chain doesn't rub the cover. Later years SBC went to the plastic front cover with the one piece oil pan gasket. When the oil pan goes back on paying attention to the corners of the gasket and super clean everything and RTV a little in each corner. The leaks on those one piece gaskets are at the 4 corners. For RTV sealers tried many, use the GM for those pan areas and intake manifold, it's gray. https://www.summitracing.com/parts/nal-88864346
Also like the GM https://www.summitracing.com/parts/ado-10-2024
for the bolts that need sealant, head and intake manifold. If you use new head bolts that come with sealant on the threads, Dorman for one, judiciously apply more to insure 100% seal of head bolts. Been there done that.
Lucky you, the car is so low mileage that many things are not even broke in yet but are after all 35 years old. The P/S hoses are one of those things. If you replace the high pressure hose on the P/S you can eliminate that switch on the steering box that turns off the A/C compressor if the pressure in the P/S system goes high. That happens when you hold the steering full lock one direction and pump pressure goes high, engine rpm slow down due to extra pump load, the switch turns the A/C compressor off until pressure goes down again. That was something GM had to do for Grandma in the parking lot.
Edelmann makes the necessary hose, bolt in, eliminates the switch, EDELMANN 71074, used on the non A/C cars. Edelmann hoses were good stuff several years ago, USA, who knows now. Rickauto says 7 bucks, wow.
Motor mounts. If your's are still in good condition, not oiled, not cracked or separated reuse them. Poly motor mounts will add harshness and more vibration feel into the steering wheel. Motor mount and steering box are side by side. The aftermarket rubber mounts are less than 20 bucks a pair, but i question quality. Bought Anchor mounts and looked at them, hmmm, definitely cheaper. Why am I putting 500/500 on these mounts with launching in mind. Was lucky enough to get one of the last GM sets before they went overseas,. #22188497, list price is 137, each! So reuse your mounts if possible. Ran the GM mounts for a few year. In search of wheel hop problems change to black Energy poly mounts, yep, noticed the difference in the steering wheel. Doesn't help the steering intermediate shaft has no dampening now.
Always a good idea to have the radiator tested. The G rads I was told were thin to start with and that's why the original 86 rad was to his shop for core leaks twice. The third time it leaked a new copper/brass 4 core was bought, small company up where all the lakes freeze, dirt track guys were using his rad, more durable to take the punishment.. Got 20 years on that rad now, soon time to service it again, cooking, cleaning, pressure testing and a light fresh coat of rad paint The evap get a cleaning at that time too. Lots of winged stuff get in there.
Bored in suburbia.