Here is the helmet spec's right of the NHRA site.
Page 282
10:7 HELMET
Drivers of NHRA Lucas Oil Drag Racing Series and E.T. cars (13.99 or quicker) must use a
helmet meeting Snell SA2000, M2000, SA2005, M2005, M2010, 2007 or SFI 31.1A,
31.2A, 31.1/2005, 41.1A, 41.2A, or 41.1/2005 Specs. Drivers in supercharged, frontengine,
open-bodied cars and Funny Cars must wear a helmet meeting Snell SA2000,
SA2005 or SFI 31.1A, 31.2A, or 31.1/2005 Specs. See Class Requirements.
NHRA Helmet Expiration Dates
Label Expires
Snell 2000 1/1/2012
2010 NHRA Rule Amendments
As of October 26, 2009
53
Snell 2005 1/1/2017
Snell 2010 2007 1/1/2022 2019
SFI 31.1A 1/1/2014
SFI 31.2A 1/1/2014
Label Expires
SFI 41.1A 1/1/2014
SFI 41.2A 1/1/2014
SFI 31.1/2005 1/1/2017
SFI 41.1/2005 1/1/2017
SFI 24.1 (JDRL only) 1/1/2015
SFI 24.1/2005 1/1/2017
Here is the link:
http://www.nhra.com/UserFiles/file/2010RuleBookAmendments.pdf