[dartman]

read the section "how to use this rulebook"

On the other hand, as to performance equipment, it is the general rule that unless optional performance equipment or performance-related modification is specifically permitted by this Rulebook, it is prohibited. All model, engine, or equipment changes or modifications not specifically addressed in this Rulebook must be submitted in writing to NHRA for consideration prior to competition. Approval will be granted or denied in NHRA’s sole and absolute discretion. The applicant will be notified of approval or rejection in writing from NHRA headquarters in Glendora, Cali

but in short it say"just because it doesn't say you can't and doesn't mean you can"