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Need some specs on that LB9

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Old Apr 4, 2014 | 03:21 PM
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Need some specs on that LB9

I am rebuilding the LB9 in my 85 camaro, nothing too fancy just a stockish rebuild. I am trying to figure out what pistons I need but I cant find some specs I need.
I need to know the stock compression height, quench distance, and piston head volume.

Thanks
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Old Apr 4, 2014 | 04:07 PM
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From: knoxville tn
Car: 86 IROC
Engine: 5.0 TPI
Transmission: 700-R-4
Axle/Gears: 2.73 open
Re: Need some specs on that LB9

cast flat tops with iron rings
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Old Apr 6, 2014 | 05:50 PM
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Re: Need some specs on that LB9

Bump this up, someone has to have these specs, I want to get the parts ordered so they can ship out Monday.
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Old Apr 6, 2014 | 07:50 PM
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From: knoxville tn
Car: 86 IROC
Engine: 5.0 TPI
Transmission: 700-R-4
Axle/Gears: 2.73 open
Re: Need some specs on that LB9

Originally Posted by L_C99
Bump this up, someone has to have these specs, I want to get the parts ordered so they can ship out Monday.
really?? just use stock cast flat top pistons and use cast iron rings. you DID say its a stock re build? and the valve reliefs are 6cc I think. while youre at it 0 deck the block and check the mains bore . it really does no harm to blue print the block
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Old Apr 6, 2014 | 10:16 PM
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Re: Need some specs on that LB9

Originally Posted by rusty vango
really?? just use stock cast flat top pistons and use cast iron rings. you DID say its a stock re build? and the valve reliefs are 6cc I think. while youre at it 0 deck the block and check the mains bore . it really does no harm to blue print the block
Couple things, first of all I can't find OEM parts online, i'm assuming because its so old. I also am getting the engine bored .030 over so I don't know if I can get OEM pistons in that size, plus I imagine price will be high for OEM pistons. And I don't trust that a piston is going to be right just because it says it is OEM substitute piston on ebay.
Also I would like to just get pistons with a higher compression height rather than decking the block due to cost, with stockish power the block doesn't have to be perfect. I don't think it would hurt to bump the compression ratio to 10:1 either which I can do with aftermarket pistons.
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Old Apr 7, 2014 | 08:23 AM
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From: knoxville tn
Car: 86 IROC
Engine: 5.0 TPI
Transmission: 700-R-4
Axle/Gears: 2.73 open
Re: Need some specs on that LB9

don't buy pistons from "fee bay" you can never know what youre getting. and actually if you print the block and use flat tops your compression will be somewhere around 9:50. which is about all pump gas can accomidate any way. and its cheaper too . you don't have a oreilleys anywhere around??I would get some nice TRW cast pistons they are affordable . the way to do this is buy the pistons and have the block bored to fit them. forget about buying engine rebuilding parts on line .certainly NOT from e bay. and as with any engine build quality parts and attention to detail is the difference between a short lived grenade and a engine that lasts.now im not trying to change your mind. just pointing out some things to consider
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Old Apr 7, 2014 | 06:39 PM
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Re: Need some specs on that LB9

I'm not planning on buying from ebay, I was just trying to make the point that I'm not trusting just any seller out there to get these specs right. I usually buy all my parts from Summit, I like the way their website is laid out and I can find my pistons by using specs rather than just make/model and hope they get it right. But I need to know the factory specs first which apparently no one know's...
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Old Apr 7, 2014 | 07:44 PM
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From: knoxville tn
Car: 86 IROC
Engine: 5.0 TPI
Transmission: 700-R-4
Axle/Gears: 2.73 open
Re: Need some specs on that LB9

Originally Posted by L_C99
I'm not planning on buying from ebay, I was just trying to make the point that I'm not trusting just any seller out there to get these specs right. I usually buy all my parts from Summit, I like the way their website is laid out and I can find my pistons by using specs rather than just make/model and hope they get it right. But I need to know the factory specs first which apparently no one know's...
well then ,this site may not be for you. for it seems as if you just don't seem to understand what we are trying to tell you. its not rocket science. anyway good luck with your "build"
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Old Apr 7, 2014 | 08:04 PM
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Re: Need some specs on that LB9

lol, you told me to buy cast flat tops... there are a million different cast flat tops out there, even disregarding different bore sizes there are still different compression heights and piston head volumes. All I came here to ask is what is the compression height and piston head volume of the factory pistons and what is the factory quench. None of those specs were given to me.
Even if you don't know what the factory quench distance is the factory deck height would work too. I know that a SBC 350 has a factory deck height of 9.025 but I'm not sure if the 305 is the same.
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Old Apr 7, 2014 | 08:16 PM
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Car: 1991 firebird
Engine: TBI 305 (built)
Transmission: T5
Axle/Gears: 4.10
Originally Posted by L_C99
lol, you told me to buy cast flat tops... there are a million different cast flat tops out there, even disregarding different bore sizes there are still different compression heights and piston head volumes. All I came here to ask is what is the compression height and piston head volume of the factory pistons and what is the factory quench. None of those specs were given to me.
Even if you don't know what the factory quench distance is the factory deck height would work too. I know that a SBC 350 has a factory deck height of 9.025 but I'm not sure if the 305 is the same.
I don't remember right off hand but I used speed pro hyper flattops with 5cc reliefs with pistons .013 in hole (deck surfaced .012) so they are .025 down stock on LO3 ... and my stock quench was . 040 its now .042

Edit: there should only be 2 different comp height pistons for a 305 the tallest one is what u need my compression should b about 10-10.5:1 ... a whole set of my pistons was only 151$

91' bird 305 TBI T-5, trick flow heads, 4.10 gears, full UMI setup, track times coming soon!

Last edited by 1991sleeper; Apr 7, 2014 at 08:40 PM.
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