2.76 open to 3.55 Sure Grip...expectations too high?
ome oil accumulation near a couple of the intake bolts.
That's pretty normal as the bolt-holes are open at the bottom. The factory bolts are pretty good at sealing, because the washer is tight-fitting and captive. But non-factory intake bolts will need a sealer on them.
All in all, yur doing pretty good. I look forward to your results.
If you heard air in the carb with the PCV flipped out, I'd be willing to bet a dollar the intake valve was not sealing. Redo the test and if same result, then;
To prove the intakes are leaking, you will need to remove the valve gear and redo the LD test with the pistons at the bottom.
With the air on the carb hissing, just bop the tips of the valvestems a lil with the handle-end of a hammer; Sometimes carbon gets trapped on the seat, and the bopping with airflow, usually blows it out. Your plugs are pretty clean, so I'm not expecting carbon.
By removing the valve gear, you can do this test with the pistons at the bottom, and there is no danger of the valves contacting the pistons. Furthermore, the valves cannot be held open by the lifters. So if bopping the valve stems does not cure the hissing, then the head will have to go to the machine shop. Either the valve is bent,burned or for whatever reason, not concentric with the seat. None of which you can fix in the garage...... at least I couldn't
But if the hissing goes away when you remove the valvegear, then you gotta look at your lifters and lifter preload.
You can get a visual, maybe, by removing the carb and covering the opening with a sheet of thin paper. I have not tried this, but the escaping air should at least disturb the paper....... I would imagine, unless it all goes out the tailpipes.
That just made me think of something. Going back to that hi-reading cylinder with normal LD, #6b IIRC, That could happen if the lobe is losing duration. So if the head comes off, you better check the cam lobes.
