Just done it soo many times, i put the whole car up on axle stands, take whole exhaust off, undo front ARB mounts to chassis, remove front prop / rear prop, gearbox heatshield, remove gearknob, put jack under rear of gearbox, remove starter motor / clutch cable, remove all bolts holding box to engine (10), undo gearbox xmember, lower jack to gain access to top of box, unbolt gearshift craddle from box and remove clip from shaft into box (complete c'unt of a job that one, even worse putting it back in), then i lay under the gearbox and basically bench press it off the engine, abit swearing later and its dragged out fromt he car MT75 isn't that heavy, Skyline box weighs alot more

Edited to say: if you have a scissor jack use this at the back of the engine under the sump to keep the engine level-ish