Its interesting that you guys want to compare the 6 cylinder 1/4 mile times with the record book 1/4 mile times.

The guy that were serious about racing were not running 6 cylinder motors unless it was a 6 cylinder class, or the 6 had a big advantage in some class for some reason. The fast guys were using the biggest V8 they could get their hands on, or the hottest V8 their checkbooks could back up.

The bellybutton concept developed because it didn't take very long before the smart guys figured out he could buy a V8 motor out of a wrecked car in a junk yard, and get it into his hot rod for less money then he could get the same HP out of the 6, if he could even get the same HP out of the 6. Everyone was doing it because it was the cheapest way to go faster, and for the guys supporting a family and trying to race, going faster for less money often was a matter of being able to race this week or not.

The guys with money wanted to try to shame the little guys with the belly button stuff. But those with money were changing to the big V8s, and then spending money to make them go faster.

What goes around comes around. These days every car on the track is a bellybutton. They all have exactly the same parts from the same companies designed by the same guys on the same computers. If you don't have all the parts, unless you got really lucky, you were an also ran. Modern racing is bellybutton. Innovation is dead. The 3.9 Dodge V6 in my 38 Plymouth coupe and the 5.2 Dodge in my 49 Dodge truck and no longer belly button. Those would have to be the modern Hemi or the Chevy LS, or whatever Ford is calling their 5.0 these days.