You'll be very lucky to find a Lowrey card, but try signing up for the Lowrey Forum Yahoo group and asking there. The top manual of that organ is in fact an inbuilt Kawai K1 synth, and you can get cards on eBay for them. Probably all sorts of weird synth sounds on them.I used to produce two cards that would work very well on the G700, and I may still have the master files to create them, but you'd need to have the DC16 RAM cards, and they are even rarer. Once people have them, they keep them! The other problem is that I can't just email the files. I would if I could but the disk format Kawai used was proprietary and you have to use their Q80 sequencer and K1 synth to produce the cards.
Best of luck
Andy G
It's not what you play, it's not how you play. It's the fact that you're playing that counts.