With the original style stand that’s used on the SF-901, there’s lots of headers that don’t fit around the uprights of the dyno cart.
And it seems most of those are angled inward as well, so they’re difficult to get attached to the dyno room exhaust system.

I’ve had numerous sets headers for various applications that just didn’t fit the dyno.

Certainly, some dyno cart configurations are more versatile with regards to header clearance than others.

Sometimes you just have to use what fits.