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Fall 2016 7

Back in 1964 when Peter Brock

began designing the unique compo-

nents for Shelby American’s special

GT350s, he initially mounted his de-

sign for the Mustang’s now familiar

hood scoop “backwards” to improve its

performance. The problem was that a

reversed scoop looked “wrong” to the

higher-ups at Ford, so they balked at

the idea, saying it was “rather like

wearing your shoes backwards.”

Brock tried to explain that the

base of the windscreen was a high-

pressure area that would create some

forced induction at higher speeds. Un-

convinced, the suits only partially

agreed that Brock’s aerodynamic prin-

cipals might be sound (as he’d solidly

proven by the shape of his highly con-

troversial Cobra Daytona Coupe) but

his new idea for a “backwards” hood-

scoop on the Mustang still went

against all “common wisdom” and was

eventually rejected. Conventional

practice for all race cars of the era was

to face the opening of a hood scoop into

the theoretical flow of on-rushing air.

Ford didn’t use wind-tunnels to

test new designs in that era or they

might have learned that, indeed, there

was great pressure at the base of the

windscreen, and even more at the nose

of the car. On the hood’s surface, how-

ever, just a few inches back from the

grill, the disturbed air was flowing a

couple of inches above the hood’s sur-

face; not an ideal location for pressure.

The flow off the nose of the car was al-

ready being affected by the pressure

build-up being created at the base of

the windscreen! It was this invisible

bubble of pressure that Brock wanted

to tap into to improve the GT350’s per-


The concept had already been

proven on his Daytona Coupe. The

small induction inlet was almost hid-

den in the surface of the hood behind

the slight bulge that had been created

to cover the eight stacks on the Day-

tona’s Weber carburetors. In the Day-

tona’s first test at Riverside, in

February of 1964, the inlet pressure

had been so great that it had blown

out the rubber seal between the inner

hood surface and the “turkey pan”

under the carburetors! Had this phe-

nomena not been discovered in testing

and the intake system perfectly

sealed, the ever-increasing pressure at

maximum speed might well have

caused the Daytonas to run lean and

blow their engines.

This was a speed secret that Brock

wanted to use on the GT350 Mustang,

but “common wisdom” prevailed and

his hood scoop was mounted facing

forward. It was nominally effective but

performance could have been im-

proved had hard-won experience been

used to better effect.

A correct “backwards” hood scoop

has now been incorporated on one of

the two “new” Jim Marietta-built pro-

totype GT350R2s being developed by

Jim’s Original Venice Crew. Further

track tests should soon confirm the va-

lidity of the idea.

Other originally rejected (because

of cost) ideas on the new Marietta

GT350R2 Mustangs, like Ford de-

signer Klaus Arning’s Independent

Rear Suspension and an entirely new,

aerodynamically-efficient front va-

lence with flexible lower air-dam (also

by Brock) have been track-tested,

showing significantly positive results.

We almost hate to bring this up,

but Chevy started using Brock’s idea,

rejected by Ford, which they called

“cowl induction” in the late 1960s with

their Chevelles. The principle was

eventually incorporated into their Ca-

maros and Corvettes…and even pick-

trucks! Scoops may look cool but cowl

induction works!



In 1964, if anybody had told Peter Brock that fifty years later

his Daytona Coupe would still be winning races he probably

would have told them there was a better chance of a man

walking on the moon. Australian Richard Bendell’s Daytona,

designed by Ross Holder and chassis builder Michael Borland

is still competitive against current Ferraris, Porsches and

McLarens. It raced at the Sebring 12-Hours this past spring.