I remember when I was in high school my parents had a friend that installed an intake that looks like that one on an engine in his 67Impala. It looked sweet but he said he was having a hard time getting it to run right. Ive heard that chevy tried a hemi head but that the spark plugs did not install like the chryslers. This must be it. Cool
Actually GM had Smokey Yunick work on the design. When he couldn't get anymore power out of the hemisperical type head as compared to the conventional sbc head, the deal was scraped. Head would have been used in the Trans-Am cars.
I don't think they would of been used in NASCAR, as by '69 the Big Block Chevy's were all that were used. Cubic inch limits were over 400 cid. Smokey Yunick used a 427 and 414 in '68, in the '66 Chevelle "The Little Car that Could, but didn't" Nascar was scared it'd be the first over 200, and Chevy wasn't backing any racing at the time.