Heads allowed in modified stock

[SSDiv6]

Originally Posted by novanicks

Thank you for the replies.

I'm looking at a AS, BS or CM combo.

Based on the replies an "approved" head is any head which came from the factory, any head listed on the NHRA accepted list and any head which also comes from the manufacturer as an aftermarket head (ie SB2 heads).

Is there any rule or nhra technical bulletin that specifies this? I would just like to feel comfortable about any decisions on an engine by ensuring they are legal.

It has always been the policy for Comp Eliminator and Super Stock Modified classes. Any cylinder head that is available through the counter and shown in the racing parts catalog, is deemed acceptable.

As an example, Ford engines in SS/CS, run the Ford Racing cast iron N351 or N352 cylinder head. Ford aluminum heads, can run the C3, D3, and SC1 cylinder heads. The same applies to the Chevrolet splayed valve 12480146/12480147/24502517 or 12480153 heads; SB2.2 part numbers 12480011, or 24502615 Wedge aluminum racing heads or the Vortec Bowtie cast iron heads. Mopar has its own equivalent cylinder heads too. You do not find any of these part numbers in NHRA's accepted product list, however, they are in use.