Thread: Clevor motor
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Old 10-26-2010, 06:26 PM
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You've hit on exactly the right points, RB!

Your friend's Clevelands were blowing up on a regular basis because the Cleveland blocks from Ford did not have priority oiling, meaning the oil did not go to the mains from the pump, but was "shunted" there from a gallery that fed the cam. Many Cleveland fans put plugs with orifices into the gallery to force more oil down to the mains, but it was mostly all in vain, the Cleveland mains were doomed to failure from inadequate oiling. The Windsor block, on the other hand, has the priority oiling system, so it is the block to use.

The port size issue is a real issue, too....the heads that were available here in the U.S. were of three types, the 2-V open chamber desigh with small ports and valves, the 4-V closed chamber "Boss 351" heads, and the 4-V open chamber "H.O." heads. Needless to say, the open chamber heads were not performance items, whereas the Boss heads are worth their weight in gold these days IF you are building an engine that will see high RPM's for most of its life.

For a street engine, the 2-V open chambered heads offered better performance than the 4-V open chambered "H.O." equivalent because the huge ports of the 4-V heads had such huge port volume that they couldn't provide adequate intake charge velocity, and the low RPM performance was really QUITE poor compared to even the 2-V open-chambered heads.

You Aussies really do have the best of both worlds for a street engine....the 2-V closed chambered heads. These were NEVER abailable here in the U.S.A. from the factory. Every now and then a container load will make it's way here from Australia--check the offerings at the bottom of the page from the U.S.A. based Australian Ford Parts business I posted above, here it is again:

http://www.ausfordparts.com/afd2v.html

For a street engine, I'd go with the AFD alloy heads in the 2-V size....great port design adequate for 600 horsepower right out of the box, they say. That way you get the great lower RPM performance of the smaller ports on the 2-V heads, excellent flow characteristics at high RPM's, and the added benefit of being able to run a higher compression ratio with alloy vs. iron.

Now, there IS one more variation on the Cleveland I've never seen, but am definitely intrigued by.....in Australia only there was offered a 351-C block based "302 Cleveland", not a 302 block like a Boss 302, but a full size 351-C block in which the engine was destroked, yielding longer rods and a fantastic rod:stroke ratio and using the closed-chamber 2-V Australian iron heads. YEE-HAW!!!!! I bet that is one incredible small displacement engines. Don't think so? Take a look at this, a list of the best engines ever offered in the Ford Mustang, the 302 Cleveland even gets a sidebar mention in section #7, in which the Cleveland is reviewed:

http://www.autotraderclassics.com/ca...ts-65188.xhtml


I notice that the Australian Ford Products business here in the U.S.A. also offers Australian 351-C blocks.....higher nickel content. IIRC (I haven't really studied their page lately, so I could be wrong about this) they also offer the short stroke crank in the 302 Cleveland from Australia....all these would be used parts, obviously, but considering that there must be literally MILLIONS of these old blocks sitting around Australia's salvage yards, there must be a real gold mine for someone interested in importing these parts to the U.S.A.

So, the Clevor will bypass the main bearing oiling deficiencies of the Cleveland block and give the benefits of the great breathing offered by the canted-valve head design (also used on the the GM "big block", 396/402/427/454 family of engines). What's not to like?

The Cleveland motor offered smaller main journals, which gave a slight advantage in horsepower development. Ford now offers what they call a Boss 351 block, which is the Windsor design with the smaller Cleveland size main journals, sort of the best of all worlds:

"Boss 351
The Racing Boss 351 is a crate engine from Ford Racing Performance Parts. The block was based on the 351 cu in (5,752 cc) Ford Windsor engine, but uses Cleveland sized 2.75 in (69.9 mm) main bearing journals. Deck height choices include 9.2 in (233.7 mm) and 9.5 in (241.3 mm). Maximum displacements are 4.25 in (108 mm) stroke and 4.125 in (104.8 mm) bore."

I guess we here in the U.S.A. are stuck with the Windsor design if we want a mid-size pushrod engine (the new "Coyote" 5.0 engine looks GREAT, but it's OHC design). The supply of Cleveland engines is dwindling and now there are those who are using the larger 400M blocks in some of the Engine Master competitions and doing quite well, thank you very much.

Cheers from Dugly
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Last edited by YerDugliness; 10-26-2010 at 06:29 PM.. Reason: spelling
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