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Hey everyone.
I've been running 400 small blocks as long as I've been driving. My Chevelle currently has a 406 with factory 5.7 rods, factory crank, Dart iron eagle 200s, Speed pro Hyperutectics and I'm at 9.56:1. Looking toward the future, I know a veteran engine builder who has retired and is selling off his inventory. I just bought 2 standard magged and sonic tested blocks, 1 standard crank, 1 -.010 rod and standard main crank and 2 sets of 5.7 O rods. Maybe in a year or two the quest for more power will get to me or I may even break what I have. Anyway, I think I'm going to go aluminum heads with around 10.1:1 compression. I was told that I should go with forged pistons at that compression. I dont't plan on much more than 450 horse, so nothing extreme. Just looking around online, I cant't really seem to find any manufacturers that have a decent selection of forged pistons for my application that will get me the compression that I'm after. Any of you builders out there know of some manufacturers that make more than 2 or 3 pistons for what I'm doing. Any info helps, since I'm just trying to get as much info as I can before I decide which route I want to go with my next build. Thanks guys!
 

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Any of you builders out there know of some manufacturers that make more than 2 or 3 pistons for what I'm doing.
You only need one :) Without knowing what head you are planning to use its hard to say but I just looked in JE and Wiseco and they both have a piston that will be close depending on what head cc you are using. I think that pretty much all of the piston manufacturers will have something. That is probably one of the most common combinations there has been over the years.
 

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Don't get hung up on compression numbers. There is more power in headflow and cam design than in .5 point of compression.
 

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70 malibu
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Discussion Starter #4
You only need one :) Without knowing what head you are planning to use its hard to say but I just looked in JE and Wiseco and they both have a piston that will be close depending on what head cc you are using. I think that pretty much all of the piston manufacturers will have something. That is probably one of the most common combinations there has been over the years.
Bill, I'm planning on a 70ccor 72cc head. I believe I also looked at both of those manufacturers and yes, they're close. These blocks are standard deck height as of now, but milling them will only get me farther than what I'm after. Thanks for the input.
 

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With a 72 cc head a flat top is going to put you right about where you want to be as long as you dont get carried away decking the block. And also like Ray said ..... compression is not all that important for an engine like that.
 

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RaceTec/AutoTec is another source, as is Keith Black/ ICON.

You would be a lot smarter to zero deck the block and D-dish piston for tight quench and a 64cc head than to use a flat top piston, no block decking, thick composition gasket and 70-72cc head with poor quench.
A tight quench engine 1/2 point higher on compression will be less octane sensitive and less detonation prone than a loose quench clearance engine with 1/2 point less compression would be
You're better off at 10.5:1 comp and tight quench than you would be at 10:1 and loose quench.
 

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Discussion Starter #8
RaceTec/AutoTec is another source, as is Keith Black/ ICON.

You would be a lot smarter to zero deck the block and D-dish piston for tight quench and a 64cc head than to use a flat top piston, no block decking, thick composition gasket and 70-72cc head with poor quench.
A tight quench engine 1/2 point higher on compression will be less octane sensitive and less detonation prone than a loose quench clearance engine with 1/2 point less compression would be
You're better off at 10.5:1 comp and tight quench than you would be at 10:1 and loose quench.
Eric, I really appreciate the input. I never would have considered a 64cc head. Please don't find this insulting since I don't know your background in building, but is this based on experience? If it is, it's something to definitely discuss with the builder I was referred to for machine work and resizing my rods. I'd like all the information I can get before I pull the trigger on this. Thanks.
 

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Eric, I really appreciate the input. I never would have considered a 64cc head. Please don't find this insulting since I don't know your background in building, but is this based on experience? If it is, it's something to definitely discuss with the builder I was referred to for machine work and resizing my rods. I'd like all the information I can get before I pull the trigger on this. Thanks.
It's based off experience, I try to do tight quench on everything as it really reduces octane sensitivity while enhancing power and fuel mileage. I've had no problem with street iron head 400's at 10.8:1 compression and either 383 or 406 @ 11.2-11.4:1 with aluminum heads live just fine on pump super. This is modern fast burn style 64cc chambers though, not that old 64cc "fuelie" head crap....although even those are better than open chambers.
The engines I built while younger with no concern for deck height, gasket thickness, and resulting compression ratio had prblems with pump super even at just 9.7:1 w/iron heads.

I'm just saying that a D-dish piston, 64cc head and zero deck the block gets you a much better 10:1 to 10.5:1 engine that one built with a undecked block, flat top pistons and 72cc heads. That old school, flat top, open chamber "smogger build mindset" from the 1970's is not the smart way to go.
 

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Discussion Starter #11
It's based off experience, I try to do tight quench on everything as it really reduces octane sensitivity while enhancing power and fuel mileage. I've had no problem with street iron head 400's at 10.8:1 compression and either 383 or 406 @ 11.2-11.4:1 with aluminum heads live just fine on pump super. This is modern fast burn style 64cc chambers though, not that old 64cc "fuelie" head crap....although even those are better than open chambers.
The engines I built while younger with no concern for deck height, gasket thickness, and resulting compression ratio had prblems with pump super even at just 9.7:1 w/iron heads.

I'm just saying that a D-dish piston, 64cc head and zero deck the block gets you a much better 10:1 to 10.5:1 engine that one built with a undecked block, flat top pistons and 72cc heads. That old school, flat top, open chamber "smogger build mindset" from the 1970's is not the smart way to go.
That makes sense, Eric. Right now I'm running +12 dish with .020 deck and 72cc iron heads and don't have issues. I understand what you're saying and I'll look around for some deeper D dished pistons. What's your view on hypereutectic vs. forged for my compression goal? Thanks again.
 

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i think 10:1 comp and 450 Hp goals you are riding the dividing line between forged and hyper....just hyper won't forgive if you get a bad tank of gas, high temp air day, spark plug heat range 1 step too hot, timing slightly off, etc where a forged can rattle from detonation to warn you and not get damaged as easily as hypers can.
Tuning window gets wider with forged pistons, more forgiving.
Personally, I draw the line on hypers at 400 Hp...if the build is expecting more, they are a risk I don't want to take just to save a couple hundred bucks on a $3000-4000+ build
 

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In a 400 I would run forged pistons for sure. I would not want to scatter junk through the engine if it were to detonate as that's what kills Hyper pistons the most Just had a friend had that happen on his Dart 406, the Hyper piston came apart on him. I have a 406 now with flat top forged, they are a little noisy but I know they are not going to come apart on me. The compression is around 11:1 with my 66cc Vortec heads.
 

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Discussion Starter #16
Go with a Mahle pistons better ring pack then the ones listed here, I use Mahle pistons when ever I can.
I was eyeing those. Around $830 for pistons and rings is a lot of money, but I guess I'll be spending at least $4,000 on this build anyway. Good thing I'm happy with my current motor, for now....;)
 

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I like CP pistons. Their Bullet series has a wide variety of sizes. Also +1 of tight quench to help make a fast burn combustion chamber.
 
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