If there is no pressure at the bleed screw, and no tension on the parking brake cable, try and loosen the brake adjuster thru the slot, there is a rubber plug that's supposed to be in that slot to keep the water out, remove it first. Spray PB Blaster thru the slot all around in there and hit the drum and backing plate with a dead blow hammer repeatedly. It may release the brake shoes and loosen the drum. The drum register to the axle register is a very tight fit, and where the drum rusts to, making drum removal difficult, but the axle will turn. If the wheel just won't turn, it's probably a brake or bearing issue.
Did it drive to where it's parked?
Was the E brake on all of these years?
Knowing that tells us what to try next.
After loosening the adjuster, try turning the axle with a LONG bar between the studs. You may be able to then remove the drum.
If not, you could drain the rearend fluid, pull the cover, and remove the cross shaft retaining pin and cross shaft, then remove the "C" clip. That allows the axle to be pulled with an axle slide hammer, rent or borrow one.
KEEP IN MIND, PB BLASTER AND WD-40 ARE BOTH FLAMMABLE!!!!!
If you use a torch on the drum after using either, your problem will be solved, because your insurance company may be paying a claim from the car being lit on fire!
TIMINATOR
P.S. answer the questions before you get into this much further...
PLAN B.
Order a 9".
Sell the rear to someone more mechanically oriented.
