[Almighty So]

i did a tiny bit of googling for you;

seems like your only options are ebay shit and lower end shit. isis, cxracing, godspeed, etc.
no one makes stuff for these engines cause no one runs them.
if guys really get into sohc's, they're usually ebay kits or diy-ugly-welds-but-it-works style.

mazworx sort of almost provided precut/bent piping to make your own but the response was lol-worthy and they scrapped the idea.