mate its not that easy

firstly you need a good engine and box! !
to start with you will have to hammer in the bulkhead in each corner were the rocker covers would go, its best to go auto because it will obstruct the clutch pedal movement! then the hard part you need to make engine mounts and also geabox crossmember needs to be addapted to fit the gearbox, then exhausts must be made cut welded etc ! then the tricky part is the auto gearstic shift you need a transit one if you can find one but are hard to get nowdays!
also you need to wire in reverse lights and to stop the van starting in any gear apart from N or P
THE BIGGEST PROBLEM IS COOLING there is no room to put any fans and you will probly need to use p6 pullys and alternator bracket!! then also propshaft will have to be made to fit the gearbox!
after i had done mine i had it for 3+years it ran exelent ! and on a run it done 24mpg! but you need to have alot of parts and welding etc to do this but it can be done!