[DeTomaso] WTB: Ford C9OX-D 302 Intake for Goose or F4B Edelbrock

[Daniel C Jones]

> So, am looking for an old Ford C9OX-D (C9OE-D) factory aluminum piece, may
> be lettered near the t-stat opening as FORD, SHELBY, COUGAR, TIGER, or blank,
> as Ford had them made up a few different ways...but all the same intake!

The C90X intake was developed for the Muscle Parts 351W head swap.
Ford only made them two ways, with either a blank pad (as shown in
the Ford Muscle Parts catalog or with FORD lettering.  All the other
versions are copies and do not perform as well.  Also be aware that
the Ford lettered and blank versions have been reproduced as well.
The real versions have OECO stamped in very small letters on the
bottom side (back corner on thermostat side).

> Another option is an Edelbrock F4B of similar design and period.

There were a bunch of similar dual planes but the C90X was the
best of the bunch.  The F4B wasn't very good.  I know a guy (Alex
Denysenko) who is a Windsor guru (holds IHRA records with 289 and
302 Windsors) and has tested pretty much all the intakes.  Here's
how he rates the dual plane 289/302 intakes:

 Best: FoMoCo C90X
 Good: Edelbrock Air Gap, Edelbrock Performer RPM, FoMoCo Shelby
       lettered, FoMoCo Cobra lettered
 Fair: Edelbrock F4B
 Poor: Weiand Stealth, Colt 65

Super Ford magazine did a SBF intake manifold flow comparison test in
the early '80's.  Jim Miller of JME did the test and the 5 intakes
tested were all provided by Alex.  They included an Offy Port-o-Sonic,
a C90X FoMoCo, a Shelby Ram Box, an Edelbrock Toker 289, and an Offy
Dial-a-Flow.  The Torker 289 was the worst performer of the group.
Second best was the FoMoCo C90X surprisingly.  Alex claims the C90X
still bests the latest Edelbrock Air Gap Performer RPM in making power
over a wide RPM range.  The C90X was also 3 tenths of a second faster
in the 1/4 mile on a 289 Hipo Mustang.  One of the things Alex likes
best about the C90X is it's flexibility.  Some intakes are sensitive
to the engine combination and may work well one one engine but not so
well on the next.  The C90X works well on any 289/302 from stock to
street/strip.  When Jack Roush built a 302 for the 1979 Indy Pace Car
Mustang, he chose the C90X.

Here are my notes on the C90X intake:

 Blank pad of Ford lettering behind the thermostat housing
 2 tapped bosses behind thermostat housing
 Firing order on the forward runner
 C90X 9424B on back runner
 2 hole (oval) plenum
 2 tapped throttle cable bracket bosses
 2 tapped bosses on aft runner for vacuum
 tin heat shield (oil splash) on bottom (held by 2 blind rivets)
 ports measure 1" wide by 1 7/8" tall
 additional threaded boss (small diameter, down low in front)

If you are under the impression that the C90X is a low rise intake,
you are mistaken.  The C90X intake is at least as tall as an S2MS
Shelby intake.  I have both here and can measure them if you'd like.

> Old articles about modifying Goose used the Ford Intake,

The ones I have appear to use the low rise cast iron intake.
An example is the article reprinted in the Peterson "Complete Ford
Book" (1972 vintage) with the details on the Mangusta engine build-up.
The article tests some parts on a Mangusta strapped to a chassis dyno
The stock engine made 110 RWHP.  They make some claims that 110 RWHP
equates to 242 HP at the crankshaft and that 145 RWHP equates to 319 HP
at the crank, neither of which compute but who knows what sort of dyno
corrections they were applying.  According to the article, the Mangusta
had a 9.5:1 compression ratio 302 that was equipped with a stock Ford
cast iron intake and a 470 CFM Autolite 4 barrel carb that made 110 HP
@ 5500 RPM on Ak Miller's chassis dyno.  The stock engine appears to be
just a 302-2V with the 4 barrel carb from the 302-4V but not the higher
compression ratio.  The article says the lower compression was due to
the lower octane fuel available in Europe.  Jerry Potts installed 351W
heads and 10.5:1 compression pistons along with a C90Z-6250-C cam
(essentially a hydraulic lifter version of the 289 HiPo solid lifer cam
with 290 deg adv duration and 0.470" lift) but retained the stock intake
and carb (single point distributor, too).  These changes increased power
to 145 RWHP with the 470 CFM carb which they equated to 319 HP at the
crank.  Switching to a 600 CFM Autolite (still on the stock intake),
they made 155 RWHP.

The Mangusta build-up used some of the parts developed for the Ford Muscle
Parts program.  In the old Muscle Parts catalog, Ford outlines 3 levels of
changes for the 289/302 SBF: Impressor, Controller and Dominator with HP
increments for each change relative to a stock 289-2V.  Adding the C90X high
rise dual plane intake, 600 CFM Holley carb and an open element air cleaner
was good for 31 HP.  Adding the C90Z-6250-C hydraulic cam with matching
lifters and springs along with a 289 HiPo dual point distributor was worth
40 HP.  Adding tube headers was worth 15 HP for a total of 86 HP over the
200 HP 289-2V.  With these parts in place, the larger port and valve '69-'70
351W heads and 10.5:1 compression pistons were worth 32 HP.  Larger GT40
valves added 7 HP more for a total increase of 118-125 HP over the 289-2V.
Switching to a Lemans solid lifter cam brought the total increase to 144-155
HP over the base 289-2V.  Going from a 289 to a 302 was worth 11 HP.

Though the parts are mostly obsolete these days, the sequence of part
changes is still sound.  Without the C90X intake and headers, the Mangusta
modifications didn't deliver as much as they might otherwise.

Dan Jones