There was a typographical error made in the initial release of the NHRA 2012 to 2013 Rule Amendments. The correction will be incorporated in the document posted on NHRAracer.com. Please see the corrected highlighted text below for reference:
SECTION 10A: STOCK CARS, ENGINE:1, ENGINE (Page 3)
Must be same year and make as car used, aftermarket NHRA accepted cylinder blocks permitted. Equipment other than original factory-installed prohibited. Any special equipment export kit (superchargers, dealer-installed options, etc.) automatically disqualifies car. Engine must remain in stock location — height, setback, etc. Cylinder bores must not exceed
.075 .080-inch over stock. Bores are measured at top of cylinder where ring wear is not evident. Crossbreeding parts prohibited. Normal balance job (i.e., one piston/rod assembly untouched) permitted. Otherwise lightening of component parts prohibited. All carburetors, manifolds, heads, etc. must be tightened to prevent any air or fuel leaks. Vacuum lines must be securely connected or blocked off. Stroke tolerance is +/- .015-inch. Stock OEM crankshaft mandatory. Stock OEM or NHRA-accepted aftermarket crankshaft mandatory. Aftermarket crank must retain OEM configuration; (i.e., billets, knife edging, etc. prohibited). Lightening of crankshaft other than normal balance job prohibited. Cylinder blocks may be sleeved. Aftermarket SFI Spec 18.1 harmonic balancer mandatory in AAA/S through G/S and AAA/SA through G/SA. See General Regulations 1:2.