History of the Ford 351 V8 engine: Aussie connection

By: Joe Kenwright

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Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection
Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection
Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection
Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection
Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection
Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection
Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection
Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection Ford 351 V8 engine: Aussie connection

Joe Kenwright explains why the 351 V8 was so important to Australia and why not all Clevelands were created equal...

History of the Ford 351 V8 engine: Aussie connection
Ford 351 V8 engine: Aussie connection

 

History of the Ford 351 V8 engine


Ford's in your face 351 heritage

The Ford 351 story in Australia was as much about establishing new street cues for Ford’s hero models as it was about the engine. Right up until the last factory XE Falcon V8, Ford’s 351 engines  added big grunter credibility to terms as diverse as ‘Super Roo’, ‘shaker’ and ‘ESP’.

THE WINDSOR 351 (351W)

Ford’s brand new small block Challenger V8, which appeared under the first compact Fairlane’s bonnet in 1962 as a 221ci (3.6-litre), was made in Windsor, Ontario hence its name. The British Commonwealth connection meant that Windsor developments reached Australia immediately.

In 1969, a year after Ford established the timeless 302 (4.9-litre), the first 351 (5.8-litre) cubic-inch V8 was launched. The four-inch bore of the 289 (4.7-litre) was now combined with an even longer 3.5-inch (88.9mm) stroke.

The still-oversquare combination delivered a big capacity V8 that loved to rev. A specific 351W Windsor block at least 1.275-inch (32.4mm) longer and higher was developed to maintain durability. This in turn dictated a wider inlet manifold.

The 351W had specific heads with bigger valves and ports and a larger oil pump. The 351W also had a different firing order (1-3-7-2-6-5-4-8 vs 1-5-4-2-6-3-7- 8) which continued into the Cleveland, then re-appeared in Ford’s much later hot 5.0-litre High Output engines.

Despite the upgrades, 351W weight went up by only 20kg for an overall figure of just 227kg, still below Chevrolet (260kg) and Chrysler (233kg) equivalents. The 351W, with smaller heads than the later Cleveland, would still fit in smaller engine bays.

A two-barrel 351W with 250hp (186kW) was offered but not in Australia. The local version was rated at 290hp (216kW) with hydraulic lifters, 450 Autolite 4-barrel carburettor (hence 4V) and cast-iron exhaust manifolds. Because this four-barrel GT engine was offered as an option in the ZC Fairlane, a ZC 351 is more special than later Fairlane 351s with the two-barrel (2V) Cleveland.

For Bathurst 1969, the GT-HO Phase I had a larger 600 Holley four-barrel and 300hp (225kW). The GT-HO Phase II from mid-1970 was cited as the change-over point from the Windsor to the Cleveland 351. That’s not what happened.

Early in 1970, the 351 Cleveland – built in the US since the third quarter of 1969 – was dropped into the XW GT. A special interim model that combined key XW GT-HO Phase I upgrades with the GT’s Cleveland engine was sold long before the Phase II arrived.

Any Windsor-powered XW Falcon GT or ZC Fairlane 351 survivor is quite rare as the 351W was only available between June, 1969 and the February-March, 1970 changeover point. Fewer than 1300 XW GT Windsors were built. Although many Australian muscle car fans get misty-eyed over the Cleveland 4-barrel, not everyone feels that way.

The 351W was a better engine in terms of longevity and reliability, as the race teams quickly found. Its superior oiling system would allow engines to last a whole season. The smooth and progressive delivery right up to 6000rpm made for a better road car. Others claim that its 30kg weight advantage over the Cleveland, which had its extra weight at the front of the block and higher up in the heads, gave any 351W-powered model superior balance.

The irony is that the Windsor survived until 1995 as a 302 while the new Cleveland lasted from just 1970 to 1974. Ford Australia then saved the 351 from total obscurity by building a local version of the Cleveland from 1972 to 1982.

The Cleveland’s C-stamped block was later stamped GF for Geelong Foundry. In honour of these two different 351 heritages, Unique Cars presents the 351C (Cleveland) and the 351G (Geelong)!


THE CLEVELAND 351

If Ford was already building a proven and reliable Windsor 351, why invite problems by switching to an all new, heavier engine of the same capacity?

Well, because the 351 Cleveland started as a bigger engine, it could be later stretched to 400ci (6.6-litre) just as the Windsor 351 was created. Built in Engine Plant 2 in Cleveland, Ohio, the new engine combined a new block with the ‘quench’ heads trialled on the Windsor-block Boss 302.

A 20-30kg weight increase was deemed acceptable given the Cleveland would be replacing big blocks in the mid-sized US models and Mustangs.

A 351ci V8 in 1969 was of little interest to Australians beyond the muscle car versions, except Ford now owned the Fairlane local long-wheelbase segment. Ford Australia saw a steady market for a softer, more frugal version of the 351 in the Fairlane and those Falcon models which had become favourites for towing.

By offering several head designs, the Cleveland could cover more engine options than any Windsor 351. Similar to Chrysler’s local Hemi six (which wasn’t a Hemi), the Boss 302 heads featured inclined valves to increase valve size with extra curvature in the combustion chamber.

For the Cleveland’s 2V heads, the inlet valves were boosted from the 351W’s 1.843 inches (46.8mm) to 2.041 inches (51.8mm) while exhaust valves grew from 1.541 (39.1mm) to 1.654 inches (42mm).

For the 4V heads, these were increased to 2.195 inches (55.75mm) and 1.715 inches (43.6mm) respectively. A V8’s cross-flow heads allowed these valves to be staggered for extra flow and size. The downside was an increase in cylinder head and rocker cover size that limited where it would fit.

A Boss 302-type wedge-shaped closed combustion chamber, combined with a massive increase in port size and camshaft lift, defined the full house four-barrel high compression models. These 4V heads could service an engine 25 percent bigger. As a 351, these oversized valves and ports cut gas flow to a trickle at lower engine speeds reducing torque at road car speeds and boosting emissions.

An open chamber 2V head design with smaller ports for the two-barrel version replicated the Windsor’s easy-going nature with big savings in fuel and emissions.

Outputs were 250hp (186kW) at 4600rpm and 355ft.lb (479Nm) at 2600rpm for the 2V version compared to the 4V’s 300hp (224kW) at 5400rpm and 380ft.lb (513Nm) at 3400rpm. The 4V’s engine speeds for these figures read more like a peaky four than a big V8, hence the distinctive exhaust bark at high revs. The smoother, more progressive 2V engine was ideal for the local Falcon and Fairlane.

These big revs exposed a serious shortfall in an otherwise superior block. The new block casting was at least two inches (51mm) longer thanks to a new housing at the front to cover the timing chain and gears. The Windsor required a separate and complex multi-stud casing that had to be bolted to the front of the block to cover these functions.

This extra front casting also carried a coolant passage to feed both heads, a better option than routing the coolant through the Windsor’s inlet manifold. The Cleveland’s top hose attaches directly to the top of the block casting, while the Windsor’s joins the front of the inlet manifold, the easiest way to identify them.

The excess 4V head capacity allowed the 351 Cleveland to be easily tweaked for big horsepower gains by adding larger carburettors, a higher lift camshaft with mechanical lifters, higher comp and extractors, which Ford Australia exploited in later homologation models. Four-bolt main bearing caps were also available but not accessed in Australia.

Despite the higher revs, bigger bearing surfaces and extra stresses, vital oil galleries were dramatically reduced in the Cleveland block. As the top end competed for the same oil from galleries feeding the bottom end bearings, something had to give at high revs. Not an issue on most road cars, major bearing failures plagued local race teams until the end. Winged sumps, later homologated on random engines, were one of the many countermeasures.

By March, 1972 the imported 351C 2V engine was replaced by a locally produced equivalent. Towards the end of XA GT automatic production, the Australian 4V engine replaced the imported 351C 4V engine. The very last of the big-valve, quench-head US 351C 4V engines were cleared in 1973 under the bonnets of XB Falcon GT manuals along with the occasional auto.

As the US Cleveland had all too quickly run into major emissions and fuel economy issues, Ford Australia was about to extend its life way beyond its US application.

THE GEELONG 351

Why did Ford Australia build an engine that had run its course in the US and was too big for local applications? After Holden had to drop the low compression US 350, Ford Australia could offer a full-strength long wheelbase Fairlane 351 and a new standalone extra-long wheelbase LTD 351 to replace full-sized US models.

The youth market wanted performance versions of the utes and vans. There were also niche markets for the Falcon 351 wagon, Hardtops and a new Landau. A local V8 engine would then boost local content and grunt in an expanded and unrivalled RHD F-series range. Last but not least, Ford’s ongoing 351 racing program had a new local GT Hardtop to promote.

Offering an affordable local 351 against a pricier imported 302 V8 Windsor made no sense. The solution was a unique 302C using the local 351C block de-stroked to order. How many buyers who ticked the 302ci option box in later Aussie Fords knew it came with a 351 Cleveland block?

There were two US 351 Cleveland blocks. The earlier D block was replaced by a tougher Square block that first appeared in 351C 2V-optioned XY Falcons in 1971. Look for the D-shaped flat section on the extended block casting just above the fuel pump or a small square section in the same area on the Square block.

The Australian 302/351G engines featured the later Square block with heads unique to each capacity. The 302 version had a masked quench combustion chamber design similar to an early Cleveland 4V head with reduced volume for the shorter stroke and cleaner emissions. Pre-XC 302G engines had two-barrel carburettors but the post-XC emissions 302G had a four-barrel.

The 351 version featured open chamber 2V heads locally developed to work with a GT’s four-barrel carburettor and a two-barrel in other applications. A four-barrel was standardised for all 351 emissions engines from XC. The 302 quench heads bolted to the 351 will deliver an instant boost in compression ratio at the risk of detonation.

Because the ‘dirty’ big valve 4V heads had already been homologated for Bathurst, Ford could deliver these emissions versions based on an inherently cleaner engine beyond 1976.

The iconic XC Fairmont GXL 5.8, XD and XE Fairmont Ghia ESP 5.8 were the last of a kind. The 351G 4V’s smooth, high-torque nature enhanced the growing European influence with traditional US brawn. It also powered the final variant of the traditional Aussie muscle car, the XC Cobra Hardtop.

Ford then announced the end of an unbroken 50-year local Ford V8 heritage in November, 1982. It was the death of the Ford that Australians knew and loved. Even if carryover stocks allowed special V8 orders to be met until 1984, Ford had surrendered its Australian muscle car status ready to become the Falcon taxi company.

 

351 GT

Did you know?

Ford Australia produced a specially reinforced 351 block for NASCAR racing which would allow bigger bores, four-bolt mains and extra rigidity around the sump. Variable casting quality meant that most of these heavier engines had to be quietly slipped into local customer cars.

Higher temperatures in emissions engines, plus airconditioning and other loads, prompted Ford Australia to experiment with ‘pillow-shaped’ bulges in the water jackets of the Aussie block for extra cooling capacity. Again, these ‘pillow’ blocks were quietly cleared in local production models towards the end.

Global De Tomaso Panteras were fitted with the Aussie 351. Sydney De Tomaso distributor Paul Halstead exported the local V8 to win duty concessions and increase local content in local Panteras.

When he heard that Ford was about to drop the V8, Halstead raced down to Melbourne with plans to keep building and developing the Aussie 351 for the small but steady global market. On arrival, he was told he was too late. All the tooling and castings had been smashed-up and buried and that was the end of it.

 

 

*****

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> History of the 351 engine: Ford V8 review here

 

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