When should I hard block? 408 Magnum

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chaditotx

chaditotx

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What level of HP should I be concerned enough about my block that I should hard block? Looking at just over 500hp. Street car with occasional strip use.
 
MileHighDart said:
I've never even heard of it.
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Hard block is basically cement poured into the block. Half filled is considered good by most and the most you would fill the block with street use and most race useage.

This is done before bore and hone to stiffen the block and cylinder walls which would help greatly in providing a stiffer block and cylinder for ring seal & big power.

At 500hp, it’s your call.
 
At 500 HP a fill won't hurt you. You need a bigger oil pan. Your cooling system must be well thought out. You need as much coolant flow as you can get.

I've filled blocks after the machine work was done but don't like doing it. I never found anything move but I'd rather fill before machining.
 
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Depending on how far you fill it you will need looser fit between pistons and wall, I wouldn't do it for a street engine.
 
rumblefish360 said:
At 500 HP a fill won't hurt you. You need a bigger oil pan. Your cooling system must be well thought out. You need as much coolant flow as you can get.

I've filled blocks after the machine work was done but don't like doing it. I never found anything move but I'd rather fill before machining.
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Understood. I just had my overbore done and it's been torque plate honed. I am already nervous about cooling issues in south Texas. I have a 3 row aluminum radiator and a fan clutch. I plan on using a Kevko or a Milidon and possibly plumbing an oil cooler.
 
To me it depends on what block is to be filled, some could use the help more so than others. If your referring to a small block, 2 inches filled or about 1/3 of the jacket wont hurt at all in the cooling department. The heat is dissipated in the top end of the cylinder and the head not the lower skirt area. This can be used for street use with the added assurance you have the strength.
 
Rock block the the trust sides of the cylinders if ya want...Though if ***** machined right, good fasteners...and "all" is balanced...it will live harmoniously as a street/strip sans the fill at 500-560hp for as long as the rings last
 
A friend of mine tried it in a drag race motor and had a lot of problems scuffing pistons, the block was filled about 2/3 and the concrete staid cold when the pistons got hot and expanded. The top end got up to temp and you could put your hand on the bottom of the block and feel a big difference in temp. He kept making the motor looser and looser and ended up with about .012 clearance.
 
chaditotx said:
I am already nervous about cooling issues in south Texas. I have a 3 row aluminum radiator and a fan clutch. I plan on using a Kevko or a Milidon and possibly plumbing an oil cooler.
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An excellent idea running a deep pan and extra oil in conjunction with an oil cooler.
While not so hot here on the island, I do run a new radiator and a MP viscous fan with pre mixed 50/50 antifreeze because it’s mixed properly with heavy water instead of tap.

The engine isn’t a high HP mill yet. If it was another 100 hp higher, it would be an oversized aluminum radiator as well as a large oil cooler and trans cooler.
 
Thank you all for the info. What high capacity oil pan would you guys recommend for a Magnum stroker? I will be using the Magnum timing cover and would like to use the Magnum gasket.
 
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