Strength of the Cleveland block?

[cazsper]

I have read that, though the Cleveland is a great motor, the block has it limitations. Of course given the situation, all blocks have their limitations. Even my Dart Windsor block. How durable is the Cleveland block and and what point is its durability going to be an issue?

 

[hyena429]

Unless you going over 650hp the stock 4 bolt main block will be fine...It was realy well webbed too unlike old chevy small blocks and older 302 fords...It will handle as much hp as a built big block chevy...My freind is rebuilding a Gen 4 big block chevy..and it is only good up too 650-700 hp before you need to start looking into a dart block....And i heard stories of the blocks "including ford and chevy dodge" being took higher than that with out busting...But i would not trust any stock big block or cleveland too much past 700hp ..Not worth the risk......No reason to dump that much into a motor and keep the stock block anyways.......Dart blocks are the way to go anything past 700 or 800 range.

By my option...But like they say about those Everyone has one..lol..But i have read wild stories of stock block clevelands being took too 1000hp.....I seen a few dyno cleveland stock blocks being pushed too allmost 800..but is it safe for long term? Not sure...lol

 

[auron73mach1]

Oiling priorities in the higher rpm range and the original 2 piece valves coming apart are the only things I have seen personally and those are both easily fixed

 

[Jeff73Mach1]

Properly prepared, it should be good to over 700 horsepower.

 

[wwhite72]

The Boss motor had high nodular cast blocks, supposedlu some Aussie blocks were similiar. That would be your benchmark. The flashing in the main saddles can be cleaned up on all engines to reduce possible cracks. With a nodular crank and proven oil mods the engines spin to 7k without a problem. Then you risk rod failure or valve train problems associated with float....or head damage due to excessive spring pressures to avoid float. Its still a pushrod design. Heh heh

 

[cazsper]

Oh ok. I don't think I'll be in the HP range that I need to worry about it. If I don't plan to spin it past 6000-6500, am I going to have any issues with oiling?

 

[Jeff73Mach1]

Not unless you hold it at higher RPM for long periods of time. There is a fairly common mod to run a line from the oil galley plug above the oil filter to the back of the block where the oil pressure sending unit is located. You then add a T fitting and plumb oil there. This is the simplest external modification and does improve main oiling.

If you do so, make sure the line is secured away from the exhaust so it doesn't get burned through.

 

[wwhite72]

Moroso restrictor kit 22050 was a Jack Rousch mod for the Cleveland. helps move oil to the mains. The external is the real fix though.

 

[TommyK]

It is generally recommended that above 500 hp that at least a partial block fill be done.

 

[Wolverine]

I have read that, though the Cleveland is a great motor, the block has it limitations.

All blocks have limitations.

I have 200k+ 1970 351c 4V, 200k + miles 1973 351c 2v. All I ever did was change the oil. Original carbs, never rebuilt. Never a problem.

Now, if you want to play the 500HP game, your mileage may vary.

 

[droptop73]

The Cleveland can be built to provide well over 700 horsepower with a well prepared partially filled block. 2 bolt or 4 bolt doesn't matter too much, the outboard bolts are only 3/8". The main caps will walk no matter what you do.

Realistically, what kind of power are you looking for?

 

[cazsper]

Thank you for the info. Similiar specs in a 408w with AFR-205 heads will get me 500+ flywheel HP. I'm not looking for more than that from a smallblock.