Finch, sorry you're having pump problems
All you need is the pump model to get the seals/ gaskets (if it's a superpump, the numbers are SP 1600 C-Z-2 for the seal assy, SP 1600 R for the diffuser gasket and SP 1600 T for the housing gasket) - the motor manufacturer doesn't come into play.
I haven't been able to figure out which piece is causing the leak - however, when I have to replace a motor, I install a new shaft seal and bring a housing gasket which I'll switch out if the old one doesn't appear to have much 'meat' left to it. (quick asside for anyone who thinks I'm just trying to separate some poor pool owner from their hard earned $ - experience has taught me that the seal assys will usually fail once the impeller has been removed, even if it's new and has only been in for 5 min - so i change it (~$15) to save the owner another $65 in labor charges for me to rip the pump back apart and then change it). As a note, if you think you may just need the housing gasket, as long as you do not remove the impeller the seal assy will not be affected by pulling the housing apart, you can try to just replace the housing gasket, reassemble the pump and see if the leak is still there (BTW - the diffuser gasket won't cause the pump to leak, you'll just be wasting HP).
I wish you well with this project, let me know what pump you have and I can give you the model numbers for the different replacement parts (I gave you the ones for superpumps)