If you have a couple of friends you don't even need a winch or to build anything. I used a pipe spanning the engine compartment left to right.
Some wooden blocks against the rear seat kept the pipe from rolling forward. Tied straps to each end of the engine carrier and wrapped the straps
a few times around the pipe. Each helper slowly releases the straps a lowers the engine. Note this was on an air cooled with the tranny removed
at the same time. So exhaust, tranny, engine carrier and engine were lowered as a unit.

Lowered engine onto a piece on plywood on PVC pipe rollers. Used a floor jack under tranny. After engine is down, I think we tilted
tranny/engine and took floor jack away. Roll the baby on out!

I have also used a motorcycle jack. Two friends had this idea separately. I didn't think much of it at first...until I tried it. One guy was a motorcycle guy, the other Porsche guy.
I helped drop 3 engines that week with that method- AC Vanagon, H2O Vanagon and 911.
Works very well.

I do like the winch idea for working by yourself!

John
LiMBO
86 Wolfsburg Westfalia "Weekender"