And the answer is ... a small WAFFLE -
My Clubmans Formula (1,000cc class) lightweight Lotus Seven had a Gerrard F3 BMC "A" series lump, with all the full race components, a 649 cam and 45 DCOE Weber.
The spec allowed for sustained revs of 7,500 and momentary (up through gears) of 8,500.
Now, the Norwich Straight at Snetterton, in those days, was the longest in the UK and the lap length also the longest.
My modest motor was entered in races combined with the big boys, so mixing it with big Jags and GT40 type cars.
I could reach about 135mph two thirds down the straight watching for 7500 rpm.
But how could I resist tucking under the tail of a GT40 to take me up to over 150 mph, as they passed; it would drop my fastest lap time and possibly let me close on a rival.
There was a sort of "POP!" and a lot of ominous smoke and the "limiter" was activated!
[Incidentally, no actual rev limiter.]
A plug went incandescent and blew a hole in the top of a piston; yes that one in the snap.
How the poor thing completed the lap, I know not, but little internal damage was found when I stripped the engine down and rebuilt it with some new bits later.
Fortunately, in those heady days, there were scattered around the country, BMC dealers aligned with Abingdon, which was the competition base.
Most bits on full race applications could be ordered off the shelf and arrived within days!
Incidentally (my hint of yesterday), at Le Mans it was/is a trick used by drivers of not the quickest class of obtaining a fast lap, quicker than the car's real potential, by slipstreaming.
The Mulsanne Straight, when I used to go there, was over four miles long, so tucking under the tail of a faster car could lop a few seconds off your lap time by increasing your top speed on the straight for as long as you could hang on.
Not done it myself there, but seen it, and did do it in humble Norfolk.
150mph.jpg
