Aftermarket/Replacement Cylinder Head Rule Change

[Paul Merolla]

Boy, I didn't see that coming...aftermarket heads for SBC in Stock. With a 5hp penalty.

NHRA Tech Department makes updates/corrections to the Stock Car Classification Guide
Jan. 1, 2018



The NHRA Technical Department recently made changes to the Class Guide.

Buick 98-99 added missing pages to website

Chev 62-79 added SBC replacement heads for Stock

Chev 2015 Camaro 376 365 corrected shipping weight Stk/SS

Chev 1969 Corvette 350 300 separated auto/man transmission

Ford 2010 330 500 added Stock weight breaks

Ford 2012 330 510 added Stock weight breaks

Plym 1968 Barracuda 426 425/505 separated from non SS/AH

[PJ305]

Originally Posted by Paul Merolla

Boy, I didn't see that coming...aftermarket heads for SBC in Stock. With a 5hp penalty.

NHRA Tech Department makes updates/corrections to the Stock Car Classification Guide
Jan. 1, 2018



The NHRA Technical Department recently made changes to the Class Guide.

Buick 98-99 added missing pages to website

Chev 62-79 added SBC replacement heads for Stock

Chev 2015 Camaro 376 365 corrected shipping weight Stk/SS

Chev 1969 Corvette 350 300 separated auto/man transmission

Ford 2010 330 500 added Stock weight breaks

Ford 2012 330 510 added Stock weight breaks

Plym 1968 Barracuda 426 425/505 separated from non SS/AH

I looked up one of the Edelbrock heads for a SBC and it listed 185cc intake runner, the others were 172cc to 175cc intake runner. NHRA specs are 172cc intake and 65cc exhaust, how in the world can a stock racer use replacement heads that are so far out of whack from each other?