Re: 164 air con pumps
The earliest 164s (F, G, H and maybe J?) had a big "V" belt but later ones (even 12 valves had a ribbed "poly v" belt. Obviously the pulleys will be completely different.
At some point (might have been after "K") they would have changed over to the modern "R134a" refrigerant because the older "R12" refrigerant was banned. The two are completely incompatible and the seals in one compressor won't be suitable for the fluid in the other system. There should be a plate or sticker under the bonnet that says what refrigerant your car uses.
Finally, what seized? Normally, if the aircon isn't actually switched on, the pulley just "free-wheels". There's an electromagnetic clutch inside it (that's the "tick" you hear when the aircon is first switched on). It might just be the clutch that has failed in some way - in which case, depending on whether or not you actually want your aircon back, the simplest solution might be just to change the pulley (thus avoiding discharging the system) and leave the compressor siezed forever. Just make sure you don't connect up the wire for the electromagnetic clutch and it will never try to cut in.