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Chris,
I have a couple of questions for you. A friend of my dad's who ran alot of oval track, superlates with stock chevy blocks, 350 and 400 castings, says his engine builder never used hard block or any block fillers because because it caused core shift. These were 500-700 horsepower motors with alot of reliability, all top notch rotating assemblies. What is your opinion on block fillers in early to mid 70's chevy blocks. Both 350 and 400's. What horsepower do you need it at? Other question is would a 400 block thats been line bored require another line bore if blockfiller was added after the first lineboring? These are opinions that a friend of my dads keeps throwing at him. Your input will be appretiated since we are in the middle of building a 355.

Ed
 

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Give Devcon a call. They are very helpful in this area and have used it on these types of applications. The shrink/growth factor was none when I used it.. You will need to get the right stuff though with low shrink growth properties. I checked the cylinders in 12 areas of each cylinder and had no change (with a .0001" bore gage) after it cured.. It did wonders for my aluminum block..
 

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Wouldn't fill a stock block any more than about 1/2 way up the freeze plugs on an oval track engine. Fill material becomes a huge heat sink that transfers heat into the oil.

Filled blocks tend to go out of round, especially when subjected to sustained running & heat soaks.

If the builder's willing to use top-notch assemblies, he should give up on the stock blocks and begin to use Bowtie cases.

This way he'll have the benefit of priority main oiling, a better means to feed oil into the engine (front oiling in stock blocks is risky due to potentially thin passages), plus bore wall thickness and superior cast iron.

The weight penalty of Bowtie vs. production blocks is minimal. The only way I'd use a stock block in a late model engine is if it's a quarter mile track (like Flat Rock) and in that situation a 450 HP engine is just as likely to set fast time as 700 HP.
 

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Discussion Starter #4
I appreciate the info Rob, the motor i am building is a drag race motor. My dad just knows some oval track guys so we get alot of oval track feedback. Guess i should have made myself more clear.. We dont plan on filling the 355, but we are passing around the idea of a 400, or maybe even another 350-base motor. Thanks again.

Ed
 

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Ed,

For a drag deal you'd probably be fine but be aware that the bores are likely to go out of round while in service. Otherwise, pour away!!
 

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I'd like to examine a filled block after it's been run that didn't go out of round. So far my experience (many cases) has been that the filled blocks are excessively out of round after being run for a period of time.
 
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