Hi guys, as the title states. I recently purchased a barn find 1984 C4 Corvette (Crossfire)
It's LHD (I'm Australian so normally RHD) and was imported in 1989.

The car has sat for 6-10 years, with the only leak being power steering.

This is where I need help;
the following is stumping me on whether I continue this project or not.

Before running the car, I ran a compression test (dry tests)
RH Cyl 1-4: 175-180PSI
LH Cyl 2-4: 175-180PSI
LH Cyl 1: 0-10PSI

Our compression gauge reads out -30 from whatever reading you get, on the dry test I got a reading of around 20-30PSI (subtract 30 and its basically 0)
After adding some oil to the cylinder, I got a reading of 40 actual PSI, and then adding a tiny bit more, I ended up getting a reading of 80-90 actual psi.
On top of that, after finally getting the car running, I've discovered it has blow-by. The car is running rich, but it's not running as if one cylinder is on 0psi (it does bog down when I rev it, but that's a different problem I need to trace down.)
The car is only blowing black smoke, not white smoke. The blow-by is not astronomical, but its noticeable from the oil dipstick and engine fill cap.

I want to know, do you guys think its worn rings or stuck rings?
If you think stuck rings, what are my best options for getting them unstuck
If you think worn rings, is it worth opening that can of worms?

For reference:
Car has all new spark plugs (AC Delco) (probably need to gap them)
New fuel pump
New fuel filter
New battery
Fresh fuel

0psi dry just doesn't make sense to me, even 20-30psi. The car was supposedly running really well before it sat, how could one cylinder be SO low?
Thanks guys, desperate for suggestions here.

 

Don't forget to factor in the intake and exhaust valves, you can lose compression for a number of reasons through those. Perhaps remove the LH valve cover and both rocker arms from #1 cylinder and pressurize that cylinder with compressed air and see if it whistles! Stuck ring methods, some use ATF or Diesel introduced through the spark plug holes and time to loosen those....every once in awhile turning it over a little more by hand...this would be before attempting to run it. After running, some kind of top-end cleaner, many opinions about this. Finally, just for the heck of it, keep an eye on what's happening in the cooling system, I doubt your losing that much compression to it, but making sure it's not getting pressurized by that cylinder. I'm thinking possibly burnt/bent valve, just a guess though! Good luck👍

 

I think you might have a sticky valve, several years in 1 spot you can have a valve a little open or some kind of debris sitting on the face or gum in the stem.
I would slowly drizzle a little ATF or Rislone or Marvel mystery oil in with engine running, then shut off for a few hours. Then start up and kill every Mosquito in the land down under.
Between this and previous response should loosen any sticky things.
If needed and the car needs a tare down it's Not a horrible motor it's still a fairly basic 350

 

You can buy a cylinder leak down tester fairly inexpensively. While testing, if you have a high rate of leakage if there is air emitting from the carb, its an intake valve issue; if the air is coming out exhaust pipe, its an exhaust valve issue; and if it coming out of the oil dip stick, its the rings.

Since you have noticable blowby Id check the PVC valve and if ok it's probably the rings. Ive had SOME success with Marvel Mystery Oil and ring issues.