If I remove the aircon and air pump from my 88 chev 350 (5.7)
What do I replace the air con pulley with to fit the serpentine belt?

I bought a belt from rock Auto to fit without aircon and airpump, but it needs another pulley

 

You will need a special tool to remove the pulley, you basically are buying the tool and when you return it with receipt they refund your money. Autozone and O'Reilly have laoner tools available for that you can use to remove and reinstall the pulley. But be cautious when you go to get the tool, check it for damage and excessive wear at the counter in the store, they loan the tools out and some people damage them beyond use.

I just got through using their power steering pump pulley tool. Returned the tool and got my money back no problem.

 

Thanx for the reply Richard.
I think you misunderstood my question, or maybe I have not made it very clear.
I want to remove the aircon compressor completely.
I have already removed the air injector pum. and I need to refit the serpentine belt.
The original belt doesnt fit with the 2 pulleys removed.
I have bought a belt from Rock Auto for a 350 cu in without air injection or air condition, but it needs an extra pulley where the compressor was.
What is the answer to the missing pulley?

 

If there is no AC unit then on the passenger side accessory mounting bracket there should be a tapped hole to install another pulley for the belt system without AC.

Does this diagram help?

 

Thanks RichardX2 - do you know where I would buy such a pulley? I am in UK & often deal with Rock Auto, if they might have such a pulley? Thanks again

 

That is where I search for a lot of parts and they have the pulley in addition you will have to get the bolt to attach the pulley , if you were on this side of the big pond then it would make things a bit easier. There are the options to get a belt for a system that doesn't have AC and the tensioner pulley should take up the slack, you could also measure the length of the belt and then get one shorter.