Supporting the engine?
Don't forget, the engine has to tilt down a bit in the rear to get the trans in through the clutch into the pilot, at least mine did.
I put down 2x8s and placed ramps on those to get the car higher and stable.
Also put a bar in the back of the engine over the fenders with wood brackets I made, supported the engine with jack once trans was out.
First pic with the bar is when I pulled the k-frame. Bar came from parents farm, just a giant steel bar.
Also, instead of buying a trans jack, which would not fit under the car with the trans, I bolted a wheel dolly onto my jack.
That worked well the first 3 times I had to r&r that garbage A855, but when I put a rebuilt A833 back in, I flipped it over, built a cradle out of 2x4s that would fit over my jack.
That kept the trans from spinning over while jacking it up and made it very easy. No pic of that.