No, it doesn't. RA60's did NOT come with a T50 gearbox. If you want a T50, you've either got to get a TA22/TA23 or an AE71 or an AE86. HOWEVER, the TA22/TA23 T50 will NOT suit your 4A-C or 4A-GE engine they have the wrong splines. An RA60 will have a W50 gearbox.
Nope. It'd go in, no worries, but what's the point? The 18R is a far better starting point, or if one has modifying on the brain, you may as well go for a six or eight cylinder motor. Rhys, who sold me my TA22 and used to drive the yellow Holden one-tonner has an RA60 in Adelaide for sale with a 1G-GTE in it, registered. He mentioned something about it costing someone keen about $4,000 including freight to get it up here to buy the car. That's a pretty good deal - pity RA60's are ugly as sin.