Thanks for all the ideas!
Someone had told me a similar theory about the valves, but maybe someone can educate me - I was starting to think maybe that wasn't the issue, because I'd think in that case the oil would burn off within a minute or two? I was trying to go up a very long hill, and pushed it a little bit to see if the oil would burn off and it didn't seem like it was getting any better. There's so much smoke that it seems like something very bad is happening, so I've been reluctant to push it too much. But if it is just oil being burned off then I'm guessing it's not causing any more "damage" than already exists?
I've heard mixed reviews about Bar's Leak but may be getting desperate enough to give it a go.
I’m not a big fan of snake oil chemicals out of a can. BUT… I have had good success with several can additives.
I have never used Bar’s Leak valve seal repair. I was thinking that if I were to try it, I’d add it to my oil when I’m just about ready to change the oil. I’m skeptical that the stuff would actually effect the seals – supposedly to make them swell up. Valve stem seals are made from different material, so I have no idea the effect the Bar’s Leak will have on them.
Just as a temporary test, if the Bar’s Leak additive reduces the amount of smoke, it might indicate that one or more valve stem seals have failed.
My gut says your engine is producing excessive crank case pressure during your 1st gear under load condition. Or possibly there is a mechanical failure, like a broken ring, broken ring land, or a cracked piston.
When you pulled the spark plugs did they look the same or was any one of the four showing oil burn?
If you have eliminated a bad PVC valve. I’d do a compression check.
Gnarls.