I have a 2 bbl Holley carb on my 73 mod Mach1. 351C-4v engine. I would like to change this to an 4 bbl. Will a Holley 1850 fit my inlet? Is this an ok carb to adjust and to be suitable for my car? I also have a 4 speed toploader.

Thanks in advance.

------------------
William
M&M# 4256
MCA# 64831

68 Coupe
289
C4
3:55's/Trac-Lok

------------------
William
M&M# 4256
MCA# 64831

Be aware that below the 2bbl adapter you may have a 4bbl SPREAD-BORE intake - and a 4bbl Holley would have a different bolt pattern/fitment.... Bring us the casting number off the intake (D3ZE-?) or the measurements between the carb studs....

(Where is Dan Jones when we need him? )

quote:

---

Originally posted by capri man:
if the rear holes are obviously larger than the front, it is a spreadbore.

---

Knew a girl like that once

quote:

---

Originally posted by seikemo:
The intake have the number D3ZE-9425-AA.

---

Hmmmm,,,, In reviewing the list provided by Dan Jones in the M&M archives at:
[URL=http://www.mustangsandmore.com/ubb/Archives/Archive-000002/HTML/20000809-1-001525.html]http://www.mustangsandmore.com/ubb/Archives/Archive-000002/HTML/20000809-1-001525.html[/ URL]

...I don't see that intake part number listed. Are you sure about that number?

Maybe someone else can shine some light on this?

Ryan

P.S.
Seikemo,
You might want to read through some of the M&M 335 Series archives, there's lots of good 351-Cleveland information located in there! It's at:
http://www.mustangsandmore.com/cgi-bin/forumdisplay.cgi?action=topics&number=A%3A000002&SUBMIT=Go

I've asked around but I haven't been able to locate any definitive information on which carb bolt pattern is on your D3ZE-9425-AA intake manifold.

Regarding putting that Holley 1850 on your 351C-4V engine, that seems small (600cfm) to me. Maybe you'd be better served with a bit bigger carb, like a Holley 3310 (750cfm) with vacuum secondaries. If you aren't worried THAT MUCH about fuel mileage (I assume if you were worried, you wouldn't be driving the V8) then go with a 750cfm with mechanical secondaries.

Good Luck!
Ryan

I took away the carb and the intake has 2 big and 2 smaller holes. Than I understand it's a so called spreadbore. On top of this it's an adapter and this have 4 holes at same size. On top of this it's another adapter which only have 2 holes. ( probably to fit the 2 bbl carb I have )

The distance between the mounting holes are:
137mm ( 5.39 inch ) and 143mm ( 5.63 inch )

Regarding the "size" of the carb I have been told that approx 85% of maximum rpm will give you the cfm size.

Well, sounds like to me if you want to use your D3ZE-9425-AA intake, you'll want to use the four-to-four adapter to bolt a Holley to it, be it the #1850 or which ever size Holley you decide on using.

However, I suggest that before you remove the D3ZE- intake, you may want ot try to do some research on it to determine if it is a "good" intake or should be swapped out for some aftermarket intake.

85% of max rpm? That seems high... Consider a max rpm of 5500 rpms, that means run a carb of 4675 cfms...???

If you go to the Holley web site, they say,,,, "You take the engine cubic inch and multiply by the maximum RPM and divide by 3456. If you have an automatic transmission you will need a vacuum sec. carb, a standard transmission can use a Double Pumper carb."

Go here to read more:
http://www.holley.com/TechService/FAQ.asp?category=Carburetor

D3ZE is a cast iron spread bore intake designed for the 4300D Motorcraft
spreadbore carb. Depending on who you believe, the 4300D flows between 715
CFM and 750 CFM (Ford rated teh carb at 750 CFM, others say 715 CFM) and is
well matched to both the intake and the large port 4V cylinder heads. The
small primaries of the spreadbore design keeps the mixture speed up which
helps the large port heads work at lower RPM and the large secondaries provide
the required flow at wide open throttle. The 1850 Holley is too small and
will require re-jetting. The 4300D will be jetted correctly for a 351CJ cam
or similar. If you're interested I have a 4300D off a Pantera that I'd sell.

Ford replaced the Autolite 4100 with the Motorcraft 4300 and a spreadbore
version, the 4300D. The early 4V Clevelands got the 600 CFM square bore
4300 carbs and the later got the higher flow 4300D spread bores. Both the
4300 and 4300D use air valve secondaries with fixed jets and power valve
enrichment. Alex mentioned the 429/460 4300D Police Interceptor floats are
designed for cornering and high speed pursuit. The 4300D has the standard
Holley/Autolite bolt pattern which is unusual for a spreadbore and means
they will not directly mount up to most spreadbore manifolds, other than
factory Ford intakes. The only aftermarket intake manifolds that I'm aware
of that will directly mount a spreadbore 4300D are the Holley Street
Dominators and Strip Dominators. Those intakes have a trapezoidal plenum
opening that clears the large secondary butterflies. However, other intakes
can be made to work using an adapter spacer, though I don't like those due
to the bore spacing differences. Other spread bore intakes for the 351C
like those from Offenhauser use the more common spread bore pattern shared
by the Rochester Quadrajets and Carter ThermoQuads. BTW, Ford used a Carter
ThermoQuad carb on 351C-2V's fitted with 4 barrel carbs in Australia. Your
best source of information is a Ford factory repair manual.

> However, I suggest that before you remove the D3ZE- intake, you may want to
> try to do some research on it to determine if it is a "good" intake or should
> be swapped out for some aftermarket intake.

It's a pretty good intake. All the Ford dual plane intakes, square bore or
spread bore, aluminum or iron, have essentially the same porting. They differ
mainly in the carb pattern and material.

> Regarding the "size" of the carb I have been told that approx 85% of maximum
> rpm will give you the cfm size.

No.

> If you go to the Holley web site, they say,,,, "You take the engine cubic
> inch and multiply by the maximum RPM and divide by 3456. If you have an
> automatic transmission you will need a vacuum sec. carb, a standard
> transmission can use a Double Pumper carb."

That's the old volumetric filling formula and is conservative to the point
of being useless. If anyone is interested, I can post a lengthy derivation
and discussion of the formula and why I think it is of marginal utility. As
an alternative to the carb sizing formulas, realize that 100 HP requires 140
CFM based upon a reasonable assumption for Brake Specific Fuel Consumption
(BSFC). The BFSC assumption keeps us from having to guess at volumetric
efficiency. An engine making 350 HP uses an actual 490 CFM but that doesn't
mean a 490 CFM rated 4 barrel carb will provide the required flow. It takes
717 CFM at 1.5" Hg to equal that 490 CFM at 0.7" Hg pressure drop:

Flow @ 0.7 In Hg = (CFM Rating @ 1.5 In Hg)/SQRT(1.5/0.7)
490 = X / 1.46385
X = 717 CFM flow rating required

I knew you were the MAN to contact regarding info on the D3ZE intake and any suggested carb for Steinar's '73 Stang....

It's curious that Holley - the maker of probably more carbs than anyone else in the world - doesn't have the latest carb sizing information available on their site.....interesting,,,,,or weird, depending on how you look at it.

The volumetric sizing formula is safe for Holley. Use it and you won't
end up with a carb that doesn't meter well for your application. You
probably won't end up with a carb that's optimum, though. If you run the
carb formula for Alex's 300 HP 302 build up, it'll tell you 500 CFM is
sufficient but Alex recommends a carb between 600 and 700 CFM. Run my
sizing formula and 300 HP requires 420 CFM at 0.7 In Hg. Correcting that
to 1.5" Hg:

Flow @ 0.7 In Hg = (CFM Rating @ 1.5 In Hg)/SQRT(1.5/0.7)
420 = X / 1.46385
X = 615 CFM flow rating required

which falls within Alex's recommendations. Also, be aware that even though
they are all supposed to be rated at the same pressure drop, a 750 Holley,
750 Demon, and 750 Carter carbs may flow different numbers even though they
are all advertised as 750's.

At the present time I'm only interesting in a carb that will make my car run nice and smooth. ( With the one I use now it doesn't run well - it need full service I think and probably change of some parts. The list number is 1929, but I can't find this number any places. So I don't know which model it is.)

What is the price for your 4300D carb?

Well, I am a bit worried for the fuel cost.
Here in Norway we pay approx 7 USD/ gallon...

...one more time...thanks a lot for all the information you share with me.

Steinar