[donut]

Welcome Roybetty,

IIRC, Cyclone was a company brand, not very high end, in-expensive and easily found anywhere in the States. (at least back in the day).

I tried a "free" set of headers on my '73 K-20... They fit tight, though pretty well, until I hit a bump then the front driveshaft hit 1 tube and closed it at least halfway. I found out it's better to buy for your application.
If you can get some without paying through the nose, just order some new ones. (don't know what shops ship internationally at a reasonable cost.) A competent exhaust shop should be able to set you up with true dual exhaust off your existing manifolds.

Hope this helps.