351c Decode

[TWO PACK]

HI I HAVE A 351C FORD V8 FROM A ISO RIVOLTA DOES ANY BODY KNOW WHAT THE NUMBERS MEAN ,ALSO THE BHP -C/R HEADS 1020 61-53 DIZ DA 3 4V ROCKER BOX 00447G6HB 351C 351GP 6005a SO 1710 CAM B 6 OR 9 MANIFOLD DIZE 9425BB CARB D2ZFBB DIL13 BLOCK D2 AE CA 1L15 L6135 1717, IT HAS FLAT TOP PISTONS AND 2.19 INLET VALVES ,ALSO WHAT CAM CARB MANIFOLD I WOULD NEED TO GET 350 -400 BHP FOR STREET USE THANKS TWO PACK UK COBRA CLUB MEMBER

[Jim Colman]

I also had a 351C with the same 4v heads. 10:5-1cr. The engine featured a competition cams 280 cam, Edlebrock duel plane Performer intake manifold and a Holley 750DP carb. The motor put out about 390hp. Very streetable engine but prone to plug fouling until I finally got my carb sorted out.

Cheers
Jim

[Daniel Jones]

> 351C FORD V8 FROM A ISO RIVOLTA

What year Iso is that? I knew Iso switched to 351C's in the later
Grifos, Leles, and Fidias but I thought the Rivolta were all Chevy
powered.

> THE BHP -C/R

The early high compression 4V's were rated at 300 HP (SAE gross)
and later low compression 4V's were around 266 HP (SAE net).

> HEADS 1020 61-53 DIZ DA 3 4V

Those are probably D1ZE-DA heads which are open chamber and will yield a
compression ratio closer to 9:1. Jim, were your heads D1AE's? Those
are the high compression heads that yield 10.5:1 with flat top pistons.
Two pack, the best way to be sure is to CC the compression chambers.
The open chamber heads will be around 76 cc's and the closed chamber
heads around 64 cc's or less.

Valve train failure is the number one failure mode for a Cleveland. The
stock valves are two piece with loose fitting multi-groove keepers. If
they don't slip out of the keeper, they'll pop the head off. I learned
that lesson the hard way on a newly rebuilt standard bore engine. Punched
a fist size hole in the side of the block.

Below, I've attached some general 351C tips that I put together which you
may find helpful.

> MANIFOLD DIZE 9425BB
> CARB D2ZFBB DIL13

Are the holes in the carb and manifold approximately the same size or
are the primaries smaller than the secondaries?

> BLOCK D2AE CA

D2AE-CA can be either a 2 bolt or 4 bolt main block. Drop the pan
and see. Also check the oil pan for a crank scraper and baffle plate
around the pick up.

> IT HAS FLAT TOP PISTONS AND 2.19 INLET VALVES

Okay.

> WHAT CAM CARB MANIFOLD I WOULD NEED TO GET 350 -400 BHP FOR STREET USE

A Blue Thunder dual plane high rise intake would likely be your best
bet. Available from Marino Perna at Panteras East.

> THANKS TWO PACK UK COBRA CLUB MEMBER

You might try contacting the UK Detomaso club. Panteras also came
with 351C's (and ZF transmissions). They might be able to help you
with local sources of parts.

Dan Jones


Some basics of Cleveland building (in no particular order):

- Use single piece stainless steel valves with single groove keepers. Valve
train failure is the number one failure mode for a Cleveland. The stock
valves are made from two pieces, friction welded together. They also use
loose fitting multi-groove keepers (the keepers halves contact each other
instead of being wedged against the stem by retainer.). If they don't slip
out of the keeper, they'll pop the head off. Unfortunately, I learned this
lesson the hard way. Aftermarket tight fit multi-groove keepers and valves
are available but most just switch to conventional single groove valves and
keepers.

- The 351C block is a thin wall casting with a fair amount of core shift.
Keep the overbore to a minumum and don't exceed 0.030" without sonic
checking. Individual cylinders can be offset bored to maximize wall
thickness. 1/2 fills of the water jacket with Hard Block (essentially
furnace cement) can stiffen the bottom end an cylinders and still be run
on the street.

- The rubber intake manifold gasket end seals can be troublesome, especially
if the heads and/or intake have been milled. Many builders toss the rubber
seals and just lay down a bead of RTV. I don't like this as I've seen too
many engines with RTV bits clogging up pushrod holes and oil pick ups. I
prefer to buy or make my own end seals from cork. I peen the block rails
with a punch so the gasket won't squeeze out while it's being torqued down
(a problem when the heads have been milled but not the intake). This also
works well on valve cover gaskets. Use Permatex 300 or a contact cement
to hold the gaskets in place. Don't use RTV except in the corners of the
end rails and even there I prefer using the red/brown hardening Permatex
(different from the black 300 Permatex). Retain the turkey pan unless the
carb heat ports are blocked. The pan protects the oil from splashing on
the hot exhaust crossover port and turning to ash.

- If you retain the stock rocker arms, make sure you use the steel 4V sled
fulcrums. The 2V fulcrums are aluminum and can come apart under load.
Also, there are two types of stock rocker arms (lugged and unlugged).
The ones with the lug on top may have a clearance problem with cams of
0.550" or greater lift. The pushrod tube may contact the lower position
of the rocker arm when the valve is fully open. This can bend or break
the pushrod. Given the high lift of the typical Cleveland performance cam,
roller rocker arms are a good investment for increased valve guide life.
The strongest roller rockers are the stainless steel ones from Crower,
Comp, and Norris. While they may weigh more than similar aluminum roller
rockers, the mass is concentrated at the stud so the extra inertia is
minimized. Stay away from the inexpensive, imported, aluminum roller
rockers as many are poorly made. Good aluminum roller rockers will last
a long while on most street/strip engines but very high spring pressures
can split the bodies in half. Always disassemble new roller rockers and
clean them. You may have some clearance issues with roller rockers and
the valve covers. If your valve covers are equipped with drip rails (as
Boss/HO cast aluminum and even some factory steel valve covers were), you
will have to remove them or bend them out of the way. You may also have
to clearance the rockers arms near the oil filler and PCV baffles. Use
the real FoMoCo rubber valve cover grommets. The repos just don't fit
right and will leak. Fel-Pro makes a thick three layer (cork-metal-cork)
valve cover gasket that can make the difference with clearance problems.
Permatex the gaskets to the valve covers and run them dry on the head side
if you plan on frequent removals. It is possible to run adjustable valve-
train, roller rockers and a stud girdle under a Boss aluminum valve cover
and there are spacers if more room is needed. Ford Motorsport also makes
tall polished aluminum valve covers.

- Drive a second shear pin in the distributor gear or replace with a hardened
pin. If a little debris (see valve seals below) gets in the pump gears, it
can shear or bend the pin. This retards the timing which leads to sluggish
performance and overheating, if the engine manages to continue to run at
all.

- Don't use umbrella valve seals. Use the blue or black viton seals. The
umbrella seals disinegrate over time and fall into the pan where they get
sucked up by the oil pump, momentarily locking up the pump and bending the
shear pin. Newer umbrella seals may be made of a more durable material
(the last rebuild gasket set had a note to that effect). The white Teflon
seals with the upper ring are too effective and do not allow enough oil
past for guide lubrication. This can lead to a stuck valve or prematurely
worn guides and/or stems.

- The usual Ford oil filter has a bypass valve bult into the filter which
can allow unfiltered oil to bypass the filter. The bypass can also fail,
causing a loss of oil pressure. Consider using Purolator oil filter
number L30119. It's a full size replacement for the FL-1A Ford/PH8A Fram
filter. It has no bypass spring in the middle but it does have the rubber
flapper for anti-drainback. The original application is for a 1978 Nissan
510, 2.0L 4 cyl engine (L20B) which had the bypass valve in the engine
block. This filter cross-references to a Fram PH2850, a Motorcraft FL-181,
and a Wix 51452. However, those filters have not been verified and may
still have the bypass. It appears after 1978, Nissan went to a half height
filter. Purolator part number L22167 fits that application and does not
have the bypass spring but does have the rubber flapper for anti-drainback.
Serious engines may want to run dual filters.

- The stock rods are good to 7000+ rpm with prep. At a minimum, use good
(ARP) rod bolts. Beam polishing and shot-peening are also good but
optional.

- Run a PCV valve.

- Use a Cleveland specific thermostat. They have a shoulder which is sized
to match the brass restrictor ring in the block (make sure it's there)
which other thermostats do not have. Using a Windsor thermostat (which
the parts counter monkeys will give you half the time) will lead to over-
heating because coolant will bypass the radiator. Don't run an excessively
cool thermostat. It won't make a difference in steady state temperature
but will slow warm-up time. I recommend the Robert Shaw 351C thermostat.
It's quick acting and has bleed provisions (ball bearing check valve).

- 4 bolt mains are a nice-to-have but not necessary for most applications.

- If the car is set up to handle, use a baffled, oversize, oil pan. A stock
Pantera with slicks can pull over 1.0 g's lateral and the oil in a stock
pan will climb the side of the pan starving the bearings for oil. I know
two Pantera engines that were ruined that way.

[Daniel Jones]

- The MPG "Stinger" exhaust port plates may be worthwhile for 4V heads if the
header doesn't turn down sharply at the port exit. The intakes port plates
may be more of a sealing and port match hassle than they are worth. Roush
and Marino Perna at Panteras East make intake port stuffers that go inside
the intake port. A thin layer of epoxy is used to bond the stuffer to the
pot and set screws are used to hold it in place.

- Quench heads (2V Aussie or early 4V) are the best for performance. They
allow higher compression for the same octane and make more power. Quench
heads have a flat area opposite the spark plug and an open area around the
plug. As the flat top piston rushes up toward the head, the area under the
flat reduces quicker than the area under the open part of the head. The
result is the mixture is forced at towards the plug. The resulting
turbulence evens out temperature and more completely burns the mixture.
More power, better fuel economy, and higher compression on the same octane.
If running a custom dished piston for forced induction or a stroker motor,
make sure there is a flat area under the quench pad. The best approach is
to have the pistons made with a reverse image of the combustion chamber.

- For street applications, flat top pistons (TRW forged or KB hypereutectic)
are generally used with the quench chambers for a compression ratio in the
10.5:1 range. Pay attention to the manufacturer's ring gap information you
plan to use nitrous.

- Quench heads run best with less spark advance (32-34 degrees) than open
chamber heads. The flame front has a longer distance to travel with open
chamber heads so they require more total advance, maybe 4 degrees or more
than a closed chamber head. A multi-strike ignition, like an MSD-6 series,
will allow an open chamber head to make peak power with less total advance.

- With an open plenum intake and some cam, I like the multi-strike ignitions
like the MSD-6AL (the -AL version comes with built-in rev limiter). They
improve cold start and low rpm performance. You can use any distributor
to trigger.

- Use a quality double row true roller timing chain set (J.P. Performance,
Cloyes, SVO, or similar). Degree in the cam and mark true TDC on the
balancer. Stay away from gimmick dampers (TCI Rattler, Fluidamper, etc.).
Stick with a stock or quality rubber elastomer type balancer (SVO/ATI,
ROMAC, etc.). Paint a stripe on for a positive indication of balancer slip.

- If you need new cam bearings, cut grooves on an old Cleveland cam to use
as a scraper or have a machine shop hone to fit. Cleveland cam bearings
were honed in the block by the factory and new ones are often too tight.

- For high rpm work with a solid lifter cam, consider the standard oiling
mods (galley restrictors and/or sleeved lifter bushings). For under 6500
rpm with a hydraulic cam, stock displacement oil pump with a higher
pressure relief spring (or shimmed) is okay. High volume pumps increase
output at lower rpm where it's generally not needed, unnecessarily loading
the cam and distributor gears and wasting power. Use the SVO, ARP, or FPP
heavy duty oil pump driveshaft. MPG Head Service (a.k.a. Cam Research)
makes a windage tray to fit the stock pan. The 351M/400 can type pickup
can be used to replace the 351C pickup. Make sure the pickup and the hole
in the mating surface align. Mellings has modifications that reduce oil
pump pressure fluctuations that they claim leads to premature distributor
gear wear.

- Check the cam and distributor gears for proper contact pattern. You may
have to adjust the position of the gear on the distributor so that it
has the proper end play (make sure it doesn't rub hard on the block).
Also, it's worthwhile to pull the distributor after a few hundred miles to
check the wear pattern. There have been a rash of cam gear problems that
may be due to improperly machined cam cores. Make sure you use the proper
distributor gear material for the cam core or cam gear. Cast iron cores
require cast iron gears, steel gears require steel gears. Bronze is soft
(sacrificial) and can be used on both but doesn't last long. There are
new polymer and coated powdered metal distributor gears which may be
suitable. Make sure oil feed hole from front main bearing is open
(improperly installed cam bearings can block the oil feed passage to the
gear mesh). You can drill an 0.030" hole in the main oil gallery plug
just behind the gear mesh to pressure-oil the cam/distributor mesh.

Crane's hydraulic and solid roller cams are made from 8620 steel and
require a compatible steel (Crane makes a machined 8620 steel distributor
gear) or bronze distributor gear. Other's like Comp lists their hydraulic
roller cams and certain street solid roller profiles as being compatible
with OEM cast iron cam gears. Their -8 part number hydraulic and street
roller cam cores are austempered ductile iron. A surface treatment hardens
the cam lobes so they can run a roller lifter. Either a cast iron or cast
steel distributor gear is compatible with the -8 cores. Not compatible are
machined steel gears like the Crane 351C part which is made of 8620 steel,
the same as a solid roller cam core. OEM and Ford Motorsport steel gears
are cast steel and would work fine with the Comp street rollers but not
their race rollers. Unfortunately, Ford doesn't make one for a 351C.
Solid roller cams are usually ground on 8620 billet cores and require
bronze distributor gears which wear rapidly.

Mallory makes a special gear for their distributors that is made for
"austempered ductile iron billets" and "proferal billet" cams that is
supposed to be compatible with the Comp austempered iron cam cores.
As I understand it, the gear is heat-treated for compatibility.
Comp has recently introduced a polymer plastic gear but I think
they are only currently available for the SBF and SBC.

- Treat 2V and 4V engines as completely different when it comes to picking
components like cams, heads, and intakes. The primary difference between
2V and 4V heads lie in the ports.

- 4V heads have very large ports. The intake, though overly large for most
applications, is shaped decently enough. The exhaust is compromised to
clear the shock towers of early Mustangs and Cougars. The 4V exhaust
port has a hump then a sharp drop with an exaggerated area change. The
port exit area is very large but much of it is wasted and the flow velocity
low. The resulting intake to exhaust flow ratio isn't terrible but isn't
as good as it could be. Some builders recommend compensating by increasing
the exhaust duration and or lift, at least on milder engines. On higher
performance engines this may not be necessary and may even be detrimental.
4V heads also like a lot of lift and keep flowing more air past 0.600"
valve lift. The 4V exhaust port is sized for a 1 7/8" primary diameter
header.

- The best horsepower intake for the 4V heads is the Holley Strip Dominator.
It's a single plane and gives up low end torque but it's still smooth and
tractable. The Strip Dominator is currently out of production but can be
found at swap meets and on the 'net for $325 to $350. A close
second is the Blue Thunder high rise dual plane. It gives up a bit of top
end but has a better low end and cold weather start up. These go for
around $325 new and are available from the usual Pantera vendors. Both of
those intakes are quite tall. If hood clearance is an issue, then you're
best choices are a stock Ford intake or an Edelbrock Performer 4V (a.k.a.
F-351 4V). The Ford 4V intake were produced in iron or aluminum in square
or spreadbore (Motorcraft, not Qjet or Thermoquad) versions. The Offy Dual
Port is probably the best fuel economy, towing, intake for the 4V heads.

[Daniel Jones]

- The 2V is a whole different cylinder head, not just a 4V with smaller
ports. The oval ports are smaller, though still decently sized. The
intake ports are biased to the side to get a straighter shot at the valve.
The exhaust port is raised (relative to a 4V), has a moderate area change,
and a nice shortside radius. Though much smaller in cross-sectional exit
area (though not necessarily a smaller minimum area), the 2V exhaust port
flows as much as a 4V, with substantially higher velocities. The 2V exhaust
port is sized for a 1 3/4" primary diameter header which is more than
adequate for 400+ hp. You can use 1 7/8" diameter 4V headers on a 2V port
but you'll loose some of the scavenging effectiveness. Since the heads have
a good intake to exhaust flow ratio, they don't require an exaggerated dual
pattern cam like the 4V and work well with a single (or slightly dual)
pattern cam. Unported 2V heads tend to build flow early (have good low
lift flow) but level off after 0.530" lift or so.

- No high rise dual plane intakes exist for the 2V heads. However, the single
plane Weiand Xcelerator 2V (p/n 7516) is a good high performance intake that
works smoothly at low rpm. The Weiand's intake has ports that are larger
than those of the head. It's essentially pre-ported and requires the heads
be match ported to the intake. For a heavier vehicle, you might want to
try the Edelbrock Performer 2V (a.k.a F-351 2V). It's a low rise dual
plane with that ports match the size of the head ports. Holley made a
Street Dominator (p/n 300-12) open plenum single plane intake for the 2V
heads but it was an economy type manifold it ports smaller than the 2V head
and a small plenum. An Offenhauser Dual Port would probably be better for
fuel economy and low end. TFC, Active, and PArker (FunnelWeb) make tall
race-type single plane intakes for 2V heads.

[Bumpster]

Daniel Jones - You have impressed the living crap out of me. Just how do you know so much about these engines?

Bumpster

[Daniel Jones]

> Daniel Jones - You have impressed the living crap out of me. Just how do
> you know so much about these engines?

I've broken a few of them :-) After my first one failed due to the notorious
2 piece valve problem, I decided to do my homework before putting a new engine
together. I figured it was cheaper to learn from other's mistakes than to
make them myself so I started talking to engine builders and guys that actively
race them. Eventually, I was able to put together clear picture of the failure
modes and what to do to prevent them. I started working on a detailed web
page on the engine for the Pantera club but never got around to finishing
it, so I put together a set of quick notes which are what I reproduced above.
I also put together some notes on 351C intake manifolds and cylinder heads.

I currently have a couple of 351C-powered vehicles (a 1966 Mustang fastback
and a 1974 Pantera). I also have a '56 F100 project waiting in the wings
that was slated for one of my spare motors but I'm leaning towards putting
in a 428SCJ tri-power engine I have.

Dan Jones

[mr0077]

Dan, can you be more specific? LOL
Seriously, that's a pretty thorough treatise, interesting reading. Always liked the 351C, never got around to owning/building/(breaking?) one, though...

[TWO PACK]

HI DANIEL THANKS FOR THE INFO STILL READING OVER IT ,THE CAR IS A 1972 ISO RIVOLTA LELE 62000 MILES AND HAS NEVER BEEN STRIPED NO 177 OF 275 ,HEADS HOLD 63cc OF FLUID AND HAVE TWIN VALVE SPRINGS YELLOW PAINT .MANIFOLD DIZE 9425BB PRIMARIES ARE SMALLER. BLOCK D2AECA IS A 4BOLT MAIN AND HAS A SUMP THAT HOLDS 8 QUATS OF OIL BAFFELD AND CRANK SCRAPER ,ALSO REMOTE OIL FILTER .PISTONS ARE FLAT TOP RODS H BEAM. I AM THINKING OF SS VAVLES MANLY SINGLE GRUVE, KB HYPEREUTECTIC PISTONS CLEVITE 77 STREET CLASS 11 510/536 LIFT 214/224 dur @ .050 280/290 ADV DURATION 107/117 CENTERLINE 112 OR EDELBROCK PERFORMER CLEVITE BEARINGS CLOYES DOUBLE ROLLER TIMING SET DURABOND SEAMLESS CAM BEARINGS FEL PRO GASKETS ,HIGH MANIFOLD WILLNOT FIT UNDER BONNET EDELBROCK DUAL PLANE AND A 650 HOLLY VS .ISO HAD ZF GEARBOX 2.91 1.78 1.22 1.0 0.845 ; JAGUAR DIFF 3.31 CLAMED 165 MPH O 60 5.2 BOX DIFF ENGINE TO BE FITTED IN MY COBRA 960kl ISO 1700 kl .I WILL HAVE SIDE PIPES 4in ,PARTS WILL COME USA TO DEAR IN UK IE PLUS 40% CAR SHOULD BE FAST ON ARE SMALL LANES BUT FUEL $6.20 A GALLON .IHAVE ALSO GOT A 1941 CHEVY STEP SIDE PICK UP MADE IN ST LOUIS THANCKS DON

[fredmoss]

Hello Don, What happened to the rest of the ISO lele?