The Best way to install engine to gearbox is First install engine (take engine mounts off so engine sits low) still have the engine hanging with chains and engine lift. Have gearbox sitting on trolley jack lift the gearbox up and angle engine down till she connects most times the input will slip into possition sometimes not

ok once you are this far start as many gearbox bolts as you can I have a special long flexi drive to get the starter motor ones from underneath. The rest you should be able to get from the top. Once all the bolts are tight lift the engine up and fit engine mounts (the complete mount off the side of block)
For best results undo the sway bar from where its fixed to body (2 bolts each side) also drop the idler arm bush so the sump wont foul.
Good luck It can work easy sometimes and a real prick other times i have had the CA in and out of mine more times than I can count. I find if it starts turning to #### and things dont go rigth I leave it for an hour or two go have a few beers and relax when you get back into it all goes well

Ahh and just remember no matter how much skin, blood or tears you loose it will all be worth it once you drive it

Cheers Andrew