285/75/16 62 Series Cruiser

You are going from a 31" tyre to a 32.8". No difference in performance worth noting. ~4% difference in speedo reading, probably brings it up to around accurate, given they usually over measure by a few percent (100km/h indicated = 95 real or so)

An eyeball under the guards to see if you have enough space (ie an extra 1" or more) for clearance of the new tyres with chassis rails/steering components/suspension components should be all you need.

The issue will be getting the offset on the rims and the width of the rims right.

it should actually read5 km/h under what you are doing(100on speedo=105real) might be worth havin it callibrated just to make sure.

I have the BFG's 285/75/16 and clearance and road holding especially off road is good.

There was a power drop and the gap in the auto is a bit big for this tyre size and you have to rev out slightly higher before gear change when towing but is otherwise a good upgrade.

The perfect tyre is a 32x11.5x15 - Correct rolling diameter and only just rubs the rear inner guard on full travel

There is less tread depth on a 16 inch tyre so it will not do as many km's.

I have an 80 ('97 model) STD with 16*8 gxl rims running 285/75/16 BFG muddies. Vehicle has HHD King Coils (about 2" lift). Never had a tyre rub on any part of the car. Motor is a 1HZ with an aftermarket turbo, haven't noticed any performance drop since fitting this size tyre. By the way, the BFG web site says the 285/75/16 mud terrain to be just over 33". Speedo is about 4% inacurate: i.e. by the GPS 100kph is reading on speedo as 95-96kph.