There was enough variation and lack of consistency in the engine painting operation at each plant and between the two plants that NCRS (I'm an NCRS Master Judge) doesn't describe the overspray issues in detail in the Judging Guides (which are well over 100 pages long for each year car, and have an astounding level of detail for everything else).
All we refer to in the JG's is "slight overspray may be present on the front and rear of the aluminum intakes and water pump bypass hoses". We have judged hundreds of KNOWN-original cars (we have a "Bowtie" judging class just for unrestored/unmolested/untouched original cars), whose value is as educational tools in providing Originality guidance for the Flight Judging Guides, and they show enough variation that it would be unfair to seize on any one painting/masking configuration as being the only "correct" one.
It takes ten man-hours to Flight Judge a Corvette (five two-man teams, each of which spends 45 minutes to an hour judging Operations, Exterior, Interior, Mechanical, and Chassis), and only about four points (out of 4500 for the whole car) are related to overspray on the intake.
