[Desert1957]

I'm not sure about the swap, from larger C series trucks.
I might be able to measure a truck from work, I think we still have one with that cab style.

On your second question , the Compressor swap , I highly recomend the "Sanden" compressor, its much quieter and draws a lot less from the engine. Brackets to mount to the engine are available ,but it the hoses will have to be a custom fab job. Just mount it , buy the fittings you need with the hoses , cut to fit. Then have an A/C shop do the crimping or buy your own tool.

I don't know how much A/C experience you have , but it will be worth the swap.

Desert