CLASS RACER FORUM - View Single Post - 427-425hp w/GM 401 heads

dahkahuna · 12-06-2012, 12:29 AM

If the valve sizes have to remain stock factory spec then why is there 10 hp added to the combination? All aluminum heads in 1969 were either 1.84 closed chamber or 1.88 open chamber why would NHRA require a 1.72 valve and still penalize the engine10 hp or 80 pounds extra weight in A/SA?

12-06-2012, 12:29 AM	#4
dahkahuna Member Join Date: Jul 2006 Location: san dimas , calif Posts: 128 Likes: 0 Liked 5 Times in 3 Posts	Re: 427-425hp w/GM 401 heads If the valve sizes have to remain stock factory spec then why is there 10 hp added to the combination? All aluminum heads in 1969 were either 1.84 closed chamber or 1.88 open chamber why would NHRA require a 1.72 valve and still penalize the engine10 hp or 80 pounds extra weight in A/SA?