Conn Souaphone or Tuba with .715 bore?

[cheburashka]

Hi all,

I picked up a batch of parts on Ebay, and among them was a set of Conn valves that are 1.065 in diameter with ports that measure .718, which appears to be a Conn #10 bore. There are other parts too which suggest these are from a sousaphone. I'm hoping to pick up a beater sans pistons (cheap) that these might fit. That said, I don't need a sousaphone and am hoping they fit a more traditional bass. (I know--crazy thing to hope for, but stranger things have happened.) Conn Loyalist is missing bore size listings on most of the tubas, and doesn't show any at all that are a #10 bore. Did Conn make #10 bore tubas? If not, what was so special about that size that made them think it was only suited to sousaphones?

Thanks

[iiipopes]

14K is the standard .730 bore. I'm thinking Eb, but that may have been .690.

[cheburashka]

Pretty sure they're Conn. Christmas tree buttons and the top caps look right.

Conn Loyalist has several sousaphones listed as being this bore, including the 10K, 14K, and 22K.