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Building a second engine and need advice

nicanor

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What is a good quench for the engine? I have a high performance head gasket that is .041. How do I measure the piston in the hole so I can add that number to the .041? I'm reading that the around .045 is ideal for about 10.5-1 compression with flat top pistons.

I'm also using 440 heads (452?) instead of the 383 heads (906?) on an 383. What difference will this make?

Thank you,
Barry
 

mac

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i don't believe you will get any quench effect with those open chamber heads unless you buy a piston with the raised step. then you would have to have each cylinder measured and adjusted to make them equal.
 

nicanor

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Mac,

So you think I'm loosing tg/hp with the 452 heads on my 383?

Thanks,
Barry
 

mac

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no, i am saying that getting the quench you are looking for is not easy to get with open chamber heads.
 

moparchris

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A little light reading.

viewtopic.php?f=6&t=7550&hilit=quench

A 906 and 452 are really identical except the 452 has induction hardened exhaust seats. You really can't achieve any sort of "quench" effect with an open chamber head. Unless you digitize the chamber and have a custom piston made with a dome that matches the chamber perfectly. That will yield comp ratios in the 15 to 1 range and cost a few grand. If you really want to utilize the quench from a factory head use the 915 head.

nicanor said:
What is a good quench for the engine? I have a high performance head gasket that is .041. How do I measure the piston in the hole so I can add that number to the .041? I'm reading that the around .045 is ideal for about 10.5-1 compression with flat top pistons.

I'm also using 440 heads (452?) instead of the 383 heads (906?) on an 383. What difference will this make?

Thank you,
Barry

Read the thread above and it will explain what a "good" quench is. I use a deck bridge and a dial indicator to measure the piston deck height. You can also add half the stroke, the rod length, and the piston pin height together and subtract that number from the actual deck height of the block to achieve a theoretical deck height. No matter what the compression is the proper clearance to achieve a quench effect stays the same. How tight you can make that number is dependant on the connecting rod and weight of the piston. Read that rod stretch.
 

mcmopar

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As said, there isn't much difference between the 452 and 906 heads. Of course, the 452 will give you hardened valve seats which is a plus for running the crappy unleaded gas we have today. I am running a set on mine which have been ported and have had 2.14" intake/1.81" valves installed.
 
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