Bob,
My mate used to run a grey powered FJ that did mid 15's, but I think some did go slightly quicker. Maybe Alex would know more accurate times as he has a good collection of early magazines.
Here's a picture of the car after he turned it into a road race car, and a picture of his EH called "Bobcat". Red motor powered and ran into the 13's back in the early 70's. A couple of his other race cars are also shown.
Another one that shows the lengths people can go to get the old grey up and going, Repco cross flow head and triple webers on a grey!! Serious stuff!!