1970 340 oil pan gasket help

Torque specs are based on the minimum to keep tension on the threads. More precisely to keep threads deformed in the elastic range. Otherwise they naturally back out with vibration.
Any gasket material between bolted surfaces that is not completely compressed, or over time flows/shrinks/etc, and there is a problem.

The thick soft gaskets are often an extra problem because the pan deforms, but I mostly hate cork infill because its tedious to remove all the dried crumbly bits.

Felpro SB Oil Pan Gasket Sets, Performance (not cork)