Moparts Tech Archive

Big Block

BB Heads Q's

John Petrocelli
Moparts Member
Posts: 449
From: Freedom Pa
Registered: Apr 2001
posted 05-19-2002 04:25 PM
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I got two sets and was just wanted to know how to check to see if they were milled before.

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John Petrocelli
Moparts Member
Posts: 449
From: Freedom Pa
Registered: Apr 2001
posted 05-19-2002 05:07 PM

I look at the heads on the intake side.They got a little step that is .090 on both sets.The one set are mill .010 but I don't know if the other set maybe mill as well.Or the set that I paid to get mill .010 may not of got mill.

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BRawls
Moparts Member
Posts: 425
From: Irvine, CA USA
Registered: Feb 2000
posted 05-19-2002 06:55 PM

Easy - the bottom row of bolts holes are 1.000 thick from the factory. Measure them now and subtract that from 1.000 = amount heads have been decked

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classj
Moparts Member
Posts: 121
From:
Registered: Apr 2002
posted 05-20-2002 12:22 AM

Mabey some of the above ideas will work if you just want to know simply if they were milled.
But, if you are trying to calculate compression, the only way to know for sure is to "CC" a chamber on each head to know where your volume is at.

A piece of plexiglass or lexan with a hole in it sealed to the chamber with some grease or vasaline will do it. Put the valves in with grease on the valve seats and spark plug in and fill the chamber with rubbing alcohol. The amount is your volume. You can buy a burette for this or just use a 10cc syringe and add up the number of times you have to fill it to fill the head. That should get you close.

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Yes that works for all the bb heads and also the SB heads as well.
carl

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906 heads??? What is approx. CC's

DartGTX
Moparts Member
Posts: 516
From: Acworth, GA, USA
Registered: Nov 2000
posted 06-27-2002 04:38 PM

Need a quick number....Please help.
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Burlapen
Moparts Member
Posts: 323
From: Fresno,CA,USA
Registered: Apr 2001
posted 06-27-2002 04:42 PM

usually 88-90 cc's
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Tomaapilot
Moparts Member
Posts: 184
From: Denton, TX USA
Registered: Jan 2002
posted 06-27-2002 04:49 PM

I cut .080 off of mine, ended up with about 64cc's. I also think about 88 is right, but I know they vary somewhat.
Tom
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GY3 'Cuda
Moparts Member
Posts: 4912
From: Dorothyville, Kansas. Follow the yellow brick road until you hit Wizard St....
Registered: Dec 1999
posted 06-27-2002 04:50 PM

Yep, right around 90 cc's.

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Is the combution chamber volume of 906's 87cc's

gromski
Moparts Member
Posts: 463
From: plymouth,ct usa
Registered: Dec 1999
posted 07-17-2002 10:05 PM

This has probably been asked before didn't need to know till now>
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Sport
Moparts Member
Posts: 303
From: Canton, Ohio. USA
Registered: Jan 2002
posted 07-17-2002 11:51 PM

Yea, About, and thats about the best answer anybody can give. You will just have to measure if you want to know for sure, with YOUR head only! Sport!
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dodgefarmer
New Member
Posts: 42
From: grindrodb.c.canada
Registered: Jun 2002
posted 07-18-2002 12:40 AM

Last set that I measured came in at over 90.
Randy
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JohnRR
Moderator
Posts: 8102
From: Ma.
Registered: Nov 1999
posted 07-18-2002 12:41 AM

87 after you fiddle with them , i think thats the factory spec , none are factory spec . let me guess you just read the MM 383 article ?
i just had 2 pairs of heads checked , both sets , one head was 90 the other head was 92 , one pair are off the same untouched engine
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