32 SEPTEMBER 2017
espite its immortal tally of 27 wins at
the Indianapolis 500, Fred Offenhauser’s
eponymous and legendary engine had
become a dreadful mix of long in the
tooth and short on life by the mid-1970s.
Four decades after the stout four-cylinder
“Offy” won its first Indy 500, the sport’s
greatest powerplant was on its last legs.
Turbocharging was the Offy’s final
frontier, and with outrageous boost levels –
around 49psi forced into the combustion
chamber – the white-hot, monoblock
motors bellowed and spewed while putting
out more than 1,000hp. But the old,
heavy lumps were also starting to ventilate
at routine intervals as metal fatigued and
rotating mass became untethered.
“We were having trouble keeping the
Offy engines together,” recalls Parnelli
Jones of the eruptive 1975 season. “We
made a deal with [Offy specialist] John
Drake to use his machine and analyze our
engines. They had a lot of porosity in them.”
The leaky Offys led Jones and his long-
time business partner, Vel Miletich, to look
to their concurrent Vel’s Parnelli Jones
Racing Formula 1 program in search of
ideas. Cosworth’s high-revving, naturally-
aspirated, 3-liter DFV V8 – the engine of
choice for the majority of the F1 grid,
including VPJ – seemed ripe for an
exploratory mission in turbocharging.
A pending boost reduction for the
1976 Indy 500 hastened the search for
an alternative. At 49psi, gigantic power
figures were possible with the Offy. But
with the reduced 39psi USAC had in mind,
the venerable mill would be emasculated.
“We had to come up with something
THE X FACTOR
WORDS Marshall Pruett MAIN IMAGE RMA Paul Webb
Inspired by their in-house Formula 1 program, Parnelli
Jones and Vel Miletich spawned the DFX, an engine
that ended the Offy era and ruled Indy for a decade.
(MAIN) Mario Andretti
(No. 3) leads Roberto
Guerrero ( 9), Bobby
Rahal ( 5) and Danny
Sullivan ( 30) at
Elkhart Lake, 1984.
It’s the height of DFX
dominance in CART
and, aside from the
occasional Buick or
Chevy, the whole field