Related but unrelated, who remembers when GM engine mounts were re-designed as a "cage" style to prevent total separation when the rubber bond failed? I know it was likely at some point after 1982, because I helped someone with an '82 Cutlass Supreme that thought he needed a new transmission because when you stepped on the gas, it would pop into neutral. Engine mount was bad and let the engine lean way over, forcing the mechanical linkage into neutral.
That was somewhat more preferable of a result than my '63 Suburban that floored the gas pedal when the engine leaned over due to failed mounts.
Quick thinking had me manually shifting the TH400 (swapped) into neutral so the engine would settle back into place and let off the pedal. Come to think of it, that truck taught me a lot of "act fast" lessons, like when a brake flex hose failed at speed and I lost all brakes thanks to the single bore master cylinder setup.
Richard