Any Thoughts on Air Compressor

I would overhaul the upper half of the compressor. I mean, disassemble / pull the sleeves off and re-ring / hone if possible. Since you have already done the valve pack or whatnot. Maybe you could get 5 more years! Does your compressor have rebuild parts and data (available from aftermarket or manufacturer)?

Your pump must be pretty darn beastly if it is run by a 6hp electric motor. That's why I think a rebuild could be in order. Heck, maybe check around, maybe some operation near by can rebuild it for you? Maybe spend 200 or 300 and have a new macine for 5 - 10 years while you save up for its replacement, a radial 8 cylinder diesel 3 stage compressor :)