Air Conditioning Question

[Bri87swb]

I recently purchased an 87 swb 4x4. The previous owner had removed the original FI 305 and replaced it with a SB 350. The evaporator and accumulator are still in the engine compartment although it appears that he used some type of sealer around the evaporator enclosure. Besides the compressor, hoses, and fitting is there anything else I need to complete the sytem? I rarely use ac, so I don't actually need it. Is there some type of cover or plug for the firewall if I take the remaining ac items out of the engine compartment to clean it up?

Also the heater isn't working. The blower works, but as I move the temp. selector from cold to hot the air flow lessens and no hot air comes out. The truck is heating up fine, but the neither the hose from the water pump going to the heater-core or the return hose are warm. The heater-core might be plugged, but can you think of anything else it might be?

Thanks,

Brian