unbolt engine mounts and jack the engine up.
if it has plate mounts it will be easiest. watch all clearances and make sure your not ripping hoses and wires or crushing shit. if it has car or vmounts it will be a wresting match to remount with everything hooked up but doable...take your time and dont cross thread anything...
other then that dropping the box down is doable, if it is really clean, pulling the 3 mount bolts and maybe the steering shaft will let it sag down enough to gain clearance. should be enough to swap out the adapter. not sure what style you have that it is not changeable with the box in. but I specifically place the engine and use flat 90 adapters just for that reason.
seen boxes become loose wreck bolts and fail and ect from having dirt in there on reassembly... if you drop the box re torque a few times to make sure it is behaving...usually they are fine.
I prefer this style adapter for the 302...
https://www.summitracing.com/parts/prm-3791/overview/make/ford