The 2004 Automatic Horsepower Factoring System policy states that any run 1.40 or more under the index during a national event, Lucas Oil Drag Racing Series event, or National Open is subject to immediate horsepower increase or index decrease. As a result of 1.40-second plus runs under the index at the Atco Raceway National Open on April 16-17, the following combinations are re-rated as per policy. These changes are effective April 20, 2004.

Make/Model	CID	OEM HP	NHRA HP	HP Adjustment	New HP	Years Affected
Chevy Corvette	327	340	279	+10	289	1962-63
Dodge Challenger	340	240	289	+10	299	1972-73 (automatic)
Plymouth Barracuda	340	240	289	+10	299	1972-73 (automatic)
Chevy S-10	262	170	170	+6	176	1996
Chevy Camaro	350	275-285	325	+11	336	1993-98 (automatic)
Pontiac Firebird	350	275-285	325	+11	336	1993-98 (automatic)
Chevy Corvette	350	300	325	+11	336	1996 (automatic)