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Re: Expensive but effective way to fix detonation??
[Re: HotRodDave]
#1005611
06/05/11 03:12 PM
06/05/11 03:12 PM
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Joined: Nov 2004
Posts: 81
Oklahoma City
Spraygoon
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Thanks for all the input. After long hard thought, I am going to go with the 440 Source "Stealth Heads" which have an 80 cc chamber. If I use the KB 184 piston (I now have the 237 and both are a silvolite)i can hone and not bore. The quench pad on the 184 is .140 tall and I figure I will need to have half of that removed to get in the ballpark of .040 to .050 quench and should have a CR of 9.6. I can also deck the heads to get the CR up to 10 if I wanted and still have optimum quench.
Yes my heat risers are blocked and I appreciate all the tips but I feel if I start out with a better combustion chamber design to begin with I will be better off in the long run. I will post again in about 2 months. Anyone have reservations about the 440 Source Stealth heads??
Paul Reber
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Re: Expensive but effective way to fix detonation??
[Re: Spraygoon]
#1005612
06/05/11 06:50 PM
06/05/11 06:50 PM
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JohnRR
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Quote:
Thanks for all the input. After long hard thought, I am going to go with the 440 Source "Stealth Heads" which have an 80 cc chamber. If I use the KB 184 piston (I now have the 237 and both are a silvolite)i can hone and not bore. The quench pad on the 184 is .140 tall and I figure I will need to have half of that removed to get in the ballpark of .040 to .050 quench and should have a CR of 9.6. I can also deck the heads to get the CR up to 10 if I wanted and still have optimum quench.
Yes my heat risers are blocked and I appreciate all the tips but I feel if I start out with a better combustion chamber design to begin with I will be better off in the long run. I will post again in about 2 months. Anyone have reservations about the 440 Source Stealth heads??
Why would you do something as silly as buying pistons and cut the quench domes on them when you already have the piston you need , if you want good quench just have the block decked to put the pistons at zero , it will cost less than buying new pistons and all that machine work ?
edit ... I just reread your original post , put on the stealths , use a .041ish gasket and change the cam, buying pistons is crazy talk ....
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Re: Expensive but effective way to fix detonation??
[Re: JohnRR]
#1005614
06/05/11 09:20 PM
06/05/11 09:20 PM
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Joined: Nov 2004
Posts: 81
Oklahoma City
Spraygoon
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If I use the piston I have it puts me @ 10.6 cr with the 80 cc heads and a .039 gasket. I do not want to deck the block as it is a #'s match for the car which is kinda why I like the stealth heads. When you say change the cam, any one in particular and please give reason for doing so. BTW the piston is .010 in the hole now. The 84 cc edelbrock heads would put be compression and quench where it should be but vanity has the better of me so I am using the Stealths.
Last edited by Spraygoon; 06/05/11 09:25 PM.
Paul Reber
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Re: Expensive but effective way to fix detonation??
[Re: Spraygoon]
#1005617
06/06/11 11:00 AM
06/06/11 11:00 AM
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Joined: Jan 2003
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JohnRR
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Quote:
If I use the piston I have it puts me @ 10.6 cr with the 80 cc heads and a .039 gasket. I do not want to deck the block as it is a #'s match for the car which is kinda why I like the stealth heads. When you say change the cam, any one in particular and please give reason for doing so. BTW the piston is .010 in the hole now. The 84 cc edelbrock heads would put be compression and quench where it should be but vanity has the better of me so I am using the Stealths.
What does it being a matching number block have to do with cutting the deck? I just did the math and you piston is .007 higher than it should be so someone has definitely cut that block considering I see posted on this board that blocks are usually higher than blueprint deck?
Don't worry about the quench if you are stuck on vanity, no one ever did back in the day and the engines performed fine. Plus until you actually have a pair of stealths in your hand I would take the 80cc claim with a grain of salt , they are probably a tad bigger than that .
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Re: Expensive but effective way to fix detonation??
[Re: JohnRR]
#1005619
06/06/11 11:34 AM
06/06/11 11:34 AM
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Joined: Nov 2004
Posts: 843
Suffolk,VA
ireland383
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Suffolk,VA
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Quote:
Quote:
If I use the piston I have it puts me @ 10.6 cr with the 80 cc heads and a .039 gasket. I do not want to deck the block as it is a #'s match for the car which is kinda why I like the stealth heads. When you say change the cam, any one in particular and please give reason for doing so. BTW the piston is .010 in the hole now. The 84 cc edelbrock heads would put be compression and quench where it should be but vanity has the better of me so I am using the Stealths.
What does it being a matching number block have to do with cutting the deck? I just did the math and you piston is .007 higher than it should be so someone has definitely cut that block considering I see posted on this board that blocks are usually higher than blueprint deck?
Don't worry about the quench if you are stuck on vanity, no one ever did back in the day and the engines performed fine. Plus until you actually have a pair of stealths in your hand I would take the 80cc claim with a grain of salt , they are probably a tad bigger than that .
 my older Stealths supposedly were 84 cc and wound up being 86ish. I had them milled .030 to reach 80. I have 9.9:1 with .064 no quench and run 93 with no problems. As said check your distributor.
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Re: Expensive but effective way to fix detonation??
[Re: JohnRR]
#1005620
06/06/11 12:59 PM
06/06/11 12:59 PM
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Joined: Jan 2003
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U.S.S.A.
JohnRR
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Quote:
Do you have the vacuum advance on the distributor connected ?
You are a little light on max timing advance and that may be making the problem worse because your running a little hot ?
.050 is the edge or getting the advantage of quench , what you have now with the 452's is nothing .
HELLO ??? Also what ignition system are you using , initial timing is ?
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Re: Expensive but effective way to fix detonation??
[Re: ireland383]
#1005621
06/06/11 09:40 PM
06/06/11 09:40 PM
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Joined: Nov 2004
Posts: 81
Oklahoma City
Spraygoon
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#'s matching means you can always take it off but you can never get it back (metal on the block, yes it has been decked once) I agree with you that I should get the heads in my hands and truly see what they are, thanks. The guy @ 440 source said it shouldn't be a problem cutting 4cc (that would put me @ 9.8 with .049 quench) out of a bowl without issues but they were unwilling to do it and talking to my machine shop they were VERY uncertain about doing it.
Also the engine is already out of the car so changing plugs and timing or other things are not going to happen. However, I beleive total timing (no va) was about 28, initial was 13-15. MSD box with mallory magnetic pickup, Mallory coil.
Last edited by Spraygoon; 06/06/11 10:13 PM.
Paul Reber
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Re: Expensive but effective way to fix detonation??
[Re: Mr.Yuck]
#1005624
06/06/11 11:43 PM
06/06/11 11:43 PM
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Joined: Jan 2007
Posts: 780
Woodinville, WA
Viol8r
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Woodinville, WA
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You asked "what do you think"? Dude you have to listen to people in here. I have the TRW .140 dome piston uncut with the stealth heads at 11:1 on pump gas. Aluminum heads eat a point of compression so you will have effectively an 8:1 motor.  Have fun my friend.
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Re: Expensive but effective way to fix detonation??
[Re: Spraygoon]
#1005625
06/07/11 12:07 AM
06/07/11 12:07 AM
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Joined: Jan 2007
Posts: 7,664
IN
ahy
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Quote:
#'s matching means you can always take it off but you can never get it back (metal on the block, yes it has been decked once) I agree with you that I should get the heads in my hands and truly see what they are, thanks. The guy @ 440 source said it shouldn't be a problem cutting 4cc (that would put me @ 9.8 with .049 quench) out of a bowl without issues but they were unwilling to do it and talking to my machine shop they were VERY uncertain about doing it.
Also the engine is already out of the car so changing plugs and timing or other things are not going to happen. However, I beleive total timing (no va) was about 28, initial was 13-15. MSD box with mallory magnetic pickup, Mallory coil.
I think you are on the right track looking for a better combustion chamber/quench. The open chamber 452 and similar heads were an emissions and manufacturing compromise... not a very efficient setup. I run Ed heads and the 440 source are similar. You will get better airflow, more efficient combustion and detonation resistance. .045" - .050" quench helps... .040" is better. It would be worth considering a thinner Cometic gasket (.028" minimum from memory) to get the quench closer to .040 and compression up a bit. A CR in the low 10's should be very robust against detonation with .040 quench and your cam. My 
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Re: Expensive but effective way to fix detonation??
[Re: ahy]
#1005626
06/13/11 11:52 PM
06/13/11 11:52 PM
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Joined: Nov 2004
Posts: 81
Oklahoma City
Spraygoon
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Got the Stealth Heads Friday. One head is 80-80.5cc and the other is 82-82.5 (spread is lowest to highest chamber). I am going to have my machine shop take them apart and make sure everything is cool before I cut on them.
Question: there is a lot of meat on each side of the plug in the chamber and the plug hole has a protrusion in the casting that covers the threads, other than the fact that the plug may get a little buildup on the threads, does anyone know of any reason I shouldn't remove the protrusion. Remenber I am looking to add cc's to the chamber to lower CR a bit.
Also, I think I'll have the larger volume head decked to get 80 cc and then work on the chambers of all of them to get 84. Splitting hairs?? Overkill??
To get .040 quench here is the cc I would need to get each CR WITH the pistons I have now (KB 237's)
86=10.1
84=10.3
82=10.5
80=10.7
Last edited by Spraygoon; 06/13/11 11:58 PM.
Paul Reber
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Re: Expensive but effective way to fix detonation??
[Re: Spraygoon]
#1005627
06/14/11 12:07 AM
06/14/11 12:07 AM
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Joined: Jan 2007
Posts: 7,664
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ahy
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10.3 CR and .040" quench sounds good. The "rule of thumb" with good quench, street driven and a moderate performance cam is 10.4/10.5 max. Just a touch conservative sounds good. I went with 10.2/.040" quench and it has been very robust against detonation with a 243@.050 intake duration cam. That way if I run it hard and long, or get a tank of less than perfect tank of gas, I shouldn't hurt the engine.
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Re: Expensive but effective way to fix detonation??
[Re: ahy]
#1005628
06/14/11 12:14 AM
06/14/11 12:14 AM
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Joined: Nov 2004
Posts: 81
Oklahoma City
Spraygoon
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Just took 4cc's out of the bruette and put in in a cup, doesn't look like alot of material, I think just removing the spark plug hump should get me at least 1 cc
Paul Reber
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