10w30 is fine as long as it has enough ZDDP and your oil pressure at idle isn't too low. And no your not a dumbass you are learning, and one thing to learn real quick is maybe not the owner himself but the kids working for him love hot rod Corvettes, record the mileage and put a sticky on gauges and tell the next mechanic no one drives it. He may have to test the repairs but that's not going to add more than 50 KM's

 

Some fully synthetic oils won't cause smoke at start-up.

 

Change the PVC valve...it cheap...just in case. I would top it up and drive it for a bit. Don't worry about it for now. Just keep so extra oil around.

Call around and see how much it would cost to change that valve seals...maybe go this far. Then drive it for a bit and see if the oil consumption is gone.

Then decide what to do.

My 77 went through tons of oil. I drove it that way for a couple of years then had the entire motor rebuilt. I'm not sure what it cost were you are, Its $450 for the take out and install here plus $2100 for the rebuild. I had a mid range cam installed, a little taken off the heads, a 2800 stall converter and a shift installed. BTW I already had headers and an Excel igntion system.

 

The motor I mentioned in my last post also had a dipstick problem. The oil level was never seen as a clear level of oil. Remember, the seller told me the engine was built by a reputable shop. After tearing the engine down, I discovered whoever rebuilt the engine had it on a table, or floor unsupported. It must have rolled with the dipstick tube inserted in the block and bent it on an angle toward the crank. That angle was enough to keep the stick from going down into the pan. Instead, it caught on the edge of the windage tray and just under the crank. Fortunately, it never made contact with the rotating assembly. This engine was a good reason why not to build your own engine if you are not careful or mechanically inclined.

The tube straightened itself as I tapped it out. Building on a stand prevents this sort of thing happening, but inexcusable the builder had not recognized it having happened. Your engine had been rebuilt and no telling what the builder may have done.

 

my scoop,....... my 1979 has burned a qt every 1000 miles or so through about 5 different builds.... which have included but not limited to new performance heads... my latest build, at around 550HP at the crank still burns oil just like to original L82...I im the second owner of my C3, I purchased it it ~1981.... I recently talked to the original owner and he had a story to tell me about "burning oil" when he first got the car... The car came from Utah, and was driven her to be sold as it was not legal to sale new L82 4 speeds in Ca at that time due to smog. when he got it it "burned oil" so he had GM replace the whole engine with a new l82.... still burned about the same oil.... I did not know this at the time, so i started trying to solve the oil problem also... through every engine build, new heads, porting and polishing, various types of valve stem seals, and well... just about everything you could think of... still burnt oil..... About a year ago I was talking to an engineer at Edelbrock when i was retrofitting a new full roller "signature series" RPM cam... and we started talking about the problem with the oil.... somehow in the conversation RPM came up... I explained that at 85MPH or so im tacking about 4K... and i would run at that for several hours on end on long trips sometimes running at 5K for extended periods of time... he told me his brand new Edelbrock engines will also burn that much oil at those RPM's for those amounts of time. thus, my 383 was performing normally, ..... still burn the oil, but have noted that is is mostly burned when in high RPM situations. looks as if I have blown my Super T-10 last week, to much tq, so i will be getting a TKO with overdrive, ...... and my oil consumption should come way way down.... Are you tacking 3-4+K for periods of time? if so.... i would not worry about it to much.. p:-)

 

Mine burns a quart or so every 1000 miles or less, runs like a clock, never had a problem, runs better that my daily driver which is 25 years newer. some of it is on the garage floor and some of it has to do with the fact that every part on the motor is for racing

 

7T1Vette made brief mention of this as well and I have seen this more than once on small block Chevys. I'm almost willing to bet that most of the oil you're losing is getting sucked into your intake passages through the intake manifold-cylinder head joint. Chances are that since the engine is otherwise unmolested a simple gasket replacement will correct the problem. Since there is no valley pan to keep the hot oil out of your intake ports you can very easily lose a large quantity of oil that way. Go ahead; ask me how I know this. You may even have some loose intake bolts, check/tighten those and see if it makes any difference.

 

That is my best guess. Plugs should have oil fouling, and a good look at your exhaust smoke will reveal a tinge of blue.

 

Hey Moterhead... same here... plugs are clean... no smoke... runs like a bat out of hell... no leaks...Starts first click every time... just a race car engine...