[DeTomaso] Cleveland 2v vs 4v heads

Wed Mar 5 22:38:14 EST 2008

Here are some links to look at, as with anything regarding our cars, lots of
opinions.

You can pick up a set of Yates heads too, not cheap, but worth it.

Michael in Savannah

http://home.comcast.net/~jelerath/mustang/Specs/heads-fr.html

Let's look at some comparisons. If you have any doubt about the Cleveland
heads breathing well, compare the valve diameters to the 390, 427, 428 and
even the 460 Police Interceptor. The Cleveland 4V has a bigger intake valve
than any of the other engines except the 460 Police Interceptor! The 351C 4V
exhaust valve is only 0.020" smaller diameter than the 460 PI, and only
0.010" smaller than the high performance 427. Even the lowly 351C 2V has
intake valves larger than the high performance 390's and 428's, and the
exhausts are larger than all 390's and some 427's, 428's and 460's.

Looking at the Intake Port of the 351C 2V, you will see that it is larger
than the 390, 428 and some 427's and 460's (multiply the two dimensions).
So, while the displacement in the 351C is obviously less than the 390, 427,
428 and 460, it is designed to breathe *better* than the others and it has *
fewer* cubic inches to breathe (fill and empty). This is why the Clevelands
Rock!

If you want to compare the 351W to the 351C, you will see that the 351W
looks more like a 302 head and the 351C looks more like a standard 427 or
428 head!
The 2v heads actually work better on the street than 4v heads do, and four
barrel aftermarket intakes for 2v heads were commonly available from several
different makers, such as Edelbrock, Offy and Weiand.

The 4v chamber makes the Aussie head the "hot set-up" for street Clevelands,
and headers are the same as other 351c or 351/400m engines. Should make a
strong running combo for ya!

Both a *4V* (4-barrel carburetor) performance version and a *2V* (2-barrel
carburetor) basic version were built, both with 2 valves per cylinder. The
latter had a different cylinder head with smaller valves, smaller ports, and
open combustion chambers to suit its intended applications.

Only the Q-code 351 "Cobra Jet" (1971-1974), R-code "Boss" 351 (1971), and
R-code 351 "HO" (1972) versions have 4-bolt mains although all 335 series
engines (351C/351M/400) have space for them even in 2-bolt main form. The
main difference between 351C/351M/400 engines is connecting rod length and
main bearing size. The 351M/400 engines have the largest bearing size and
the tallest deck height while sharing the 429/460 bell
housing<http://en.wikipedia.org/wiki/Bell_housing>pattern. The 351C
engine has a medium main bearing size and shorter
connecting rods than the 351W and the 351M/400 while retaining the SBF
engine mount locations and bell housing pattern. The 400 engine has the
longest stroke of any SBF or 335 series engine.

All of the 351C and 351M/400 engines differ from the 302/351W by having an
integrated timing cover casting in the front of the block to which the
radiator hose connects.

[edit<http://en.wikipedia.org/w/index.php?title=Ford_335_engine&action=edit&section=3>
] H-code [image: 1973 H-code 2V 351
Cleveland]<http://en.wikipedia.org/wiki/Image:1973_Ford_Mustang_convertible_351-2V_Cleveland.JPG>
<http://en.wikipedia.org/wiki/Image:1973_Ford_Mustang_convertible_351-2V_Cleveland.JPG>
1973 H-code 2V 351 Cleveland

The majority of 351 Cleveland engines are H-code 2V (2-venturi carburetor)
versions with low compression. They were produced from 1970 through 1974 and
were used on a variety of Ford models, from compact to intermediate. These
engines produced about 270 horsepower.

[edit<http://en.wikipedia.org/w/index.php?title=Ford_335_engine&action=edit&section=4>
] M-code

The M-code version was produced from 1970 through 1971. Both years offered
quench heads but 1970 offered a slightly higher (advertised) 11.4:1 compression
ratio <http://en.wikipedia.org/wiki/Compression_ratio> whereas in 1971 the
chamber was opened up slightly reducing the advertised compression to 10.7:1.
The 1970 4V head is identified with the proper date code casting and a "4"
cast on the upper corner of the head. The 1971 4V head is identified with a
"4*" (four-dot) casting at the same location. Hydraulic lifters were also
specified, with the M-code producing about 300 hp (224 kW). 2-bolt main caps
were used along with a cheaper cast iron intake manifold.

[edit<http://en.wikipedia.org/w/index.php?title=Ford_335_engine&action=edit&section=5>
] 1971 R-code (Boss 351) *See also Ford Boss 351
engine<http://en.wikipedia.org/wiki/Ford_Boss_351_engine>
*

The 1971 R-code "Boss 351" used higher compression (11.7:1) with the quench
head 4V heads, solid lifters, an aluminum intake manifold, and 4-bolt main
caps. It produced about 330 hp (246 kW).

[edit<http://en.wikipedia.org/w/index.php?title=Ford_335_engine&action=edit&section=6>
] 1972 R-code

The R-code 351 Cleveland for 1972 was considerably different. It had reduced
compression for emissions compliance and used open-chamber heads. It had a
Hydraulic camshaft, however a four barrel carburetor was retained. It
produced 300 hp (207 kW) using the new SAE net system.

[edit<http://en.wikipedia.org/w/index.php?title=Ford_335_engine&action=edit&section=7>
] Q-code (Cobra-Jet)

The Q-code "351 Cobra Jet" version was produced from May 1971 through the
1974 model year. It was a low-compression design that included open-chamber
"4V" heads, a special intake manifold, special hi-lift long duration
hydraulic camshaft, special valve springs and dampers, a 750 CFM 4300-D
Motorcraft Carburetor, dual-point distributor, and 4-bolt main bearing caps.
It was rated at 280 hp (198 kW) (SAE net) for 1972 when installed in the
Mustang <http://en.wikipedia.org/wiki/Ford_Mustang> and 280 hp in the Ford
Torino <http://en.wikipedia.org/wiki/Ford_Torino> and Mercury
Montego<http://en.wikipedia.org/wiki/Mercury_Montego>.
The hp rating changed in 1973 to 246 for the 4-barrel, but showed a higher
rating for the Cobra Jet, 264 hp. Being under the net ratings system, the
engine was considered one of the sportiest of 1973, and is among the last of
the muscle-era motors. Hp ratings dropped to 246 hp (183 kW) for the
intermediate Ford and Mercurys for 1973. The 351 CJ was rated at 265 hp in
1974 and was only installed in the Ford
Torino<http://en.wikipedia.org/wiki/Ford_Torino>,
Mercury Montego <http://en.wikipedia.org/wiki/Mercury_Montego> and the Mercury
Cougar <http://en.wikipedia.org/wiki/Mercury_Cougar>.

On Wed, Mar 5, 2008 at 9:37 PM, Ken Green <kenn_green at yahoo.com> wrote:

> A "HOTPANTERA" would definitely have 4V heads.
>
>  Ken
>
> HOTPANTERA at aol.com wrote:
>  I was wonder what the thoughts were between the 2v heads or the 4v heads
> for
> a Pantera? What about a 1984 Block? Thanks for any help
>
>
>
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-- 
Michael L. Shortt
Savannah, Georgia
www.michaelshortt.com
michael at michaelshortt.com

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