UIM · Driveline
Legal in every class, same envelope everywhere.
The 12.00 mm figure is identical to IJSBA's and to IHRA's at J.18.1. One grate spec satisfies all three bodies.
24 classes, grouped by the answer rather than listed one by one, because an answer that holds for a class usually holds for every class that borrows its rules. 8 of them publish no component rules of their own and are marked below; for those, the link to the parent class is read from the categories table rather than stated in the rulebook.
Governed by the parent class 8 classes
No component rules are published for this class and no single parent class is named, so this part cannot be answered for it. That is an absence in the rulebook, not a permission.
Legal, within limits 16 classes
Full-length type with at least one bar parallel to the drive shaft, all leading edges radiused, extending no more than 12.00 mm below the flat plane of the pump intake area. GP1 adds that the projecting member must be filed so as not to create a hazard.
Aftermarket intake grate: if the rule your class applies reads differently to you, or the rulebook has changed since this was read, ask. We answer with the section we read it from, or that we have not read it. Ask a rules question.
Every UIM class · where the rulebooks differ · signed checks on parts the shop sells.
Driveline · two and four stroke · legal outright in 16 of 24