Burning a quart of oil weekly , no visible leaks .. Need help

Hello you guys need help with my taco 2000 5 speed Manual 4x4 Trd .
Has 327k original engine
Bout a couple weeks ago my engine started idling around 1800-2000rpm at cold start or even hot days
And then after a camping trip I check my oil it's below the first mark
So I added some conventional oil and drove it around and check it again and it's back below the first marker .. Been adding oil and still having the same issue ! Please help .. Hope it's not a blown h g ..thanks in advance .. (New air filter, plugs was done 6months ago , gapped also . )

 

probably valve/head problems not necessarily head gasket unless you have oil in your radiator or coolant in your oil.

 

You might want to do a compression test of the cylinders and rings. With that much mileage you might be getting substantial blowby, though I'd think with burning that much oil you'd see some smoke. These engines regularly get past that mileage without heavy oil consumption issues, as long as the oil was changed somewhat regularly.