Tillotson hw 27 a carburator manifold

[Bimodal_Rocket (Dom Callan)]

This explains the flex part: X30 Exhaust Notes — Fox + Son Karting

“Changes to the exhaust length are made by using different sizes of flexible steel pipe (referred to as “flex”) between the header and the actual pipe. A longer exhaust length gives you better bottom end power and a shorter length gives you more top end. Changing your exhaust length is akin to changing your gearing.”

Exhaust manifold:

https://www.modenakart.com/en/x30-iame/1523-unloading-connection-for-iame-x30-engine-exhaust-manifold.html

What an exhaust manifold does:
https://www.brodiestireandautomotive.com/Auto-Repair/Automotive-Q-A/mode/detail/KnowledgeItemId/2669

One piece vs 2 piece exhaust thread:

1 piece pipe vs 2 piece + flex. X30

I have limited time with an x30, 4 races but I would say adjustable would be better. There is a reason people keep 3-4 different lengths cut in their tool box. But fixed pipe will be simpler/easier.