[Amps] Doorknob caps in LK-500ZC

[Scott Manthe]

Hi ampphiles,
I've got an Amp International LK-500ZC which I'd considered selling, but 
have decided to hang onto. I want to replace the disc capacitors in the 
tank circuit with doorknobs but am not really sure what values to look 
at. According to my schematic, there is a 5kV, 1400pF cap on the 160m 
bandswitch position, 940pF on the 80m position and 470pF on the 40m 
position. Looking at the actual circuit, I'm not sure those are the 
values actually in place. Is there anyone on the list who has upgraded 
these components and can point me in the right direction? I am not an 
engineer, nor even terribly technically competent, so  please go easy on 
me with your responses.

I'd appreciate any help you guys can offer. Editorial comments about the 
relative quality of my amp compared to those made by Alpha, Acom, QRO, 
etc., etc., will not be appreciated, so save them for some other time.

Thanks in advance and 73,
Scott, N9AA