There were a lot of “givens” that Chevrolet engineers were keenly aware of in the early-1960s: 409 heads had reached their limitations, basic Wedge engines would not get the job done; Hemi engines were too bulky and heavy and valve trains way too complex for potential Corvette applications. They also knew that larger displacement engines would be needed to support Corvette sales and the factory’s Corvette racing agenda which would focus first on the aluminum-head L88 and then aluminum ZL1. The results came in 1965 with the Mark IV big-block, first displacing 396 cubic inches, and then growing to 427 and 454 inches.
To read the complete Mystery Motor story, please visit our friends at Wild About Cars
http://wildaboutcarsonline.com/cgi-bin/pub9990262549620.cgi?categoryid=9960398703582&action=viewad&itemid=9990470783495