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K I need some help on these heads I have

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Old Jan 10, 2003 | 05:13 PM
  #1  
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From: Manassas, VA
Car: 89 Formula Firebird
Engine: 305 - Demon 525
Transmission: 700R4
K I need some help on these heads I have

I need to know how to find the facts out about them that people want to know. They cost me 500.00 from some dude that could not use them cause the Rally race that he was in said they would be to much and would break the rules.


let me see if I can get a real good measuring tool... here is the pic

http://www.darkenedwolf.com/pix/heads.jpg
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Old Jan 10, 2003 | 05:15 PM
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From: Manassas, VA
Car: 89 Formula Firebird
Engine: 305 - Demon 525
Transmission: 700R4
sorry about the two post... connection is saying page cant be displayed and loaded anyway here. So please reply to this one
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Old Jan 10, 2003 | 05:52 PM
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From: Loveland, OH, US
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Look like somebody has ported the living dog snot out of the intake ports.... got 1.45" or larger valve springs on them, and screw-in studs..... can't tell too much else about them..... don't look like GM heads but I could be wrong
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Old Jan 10, 2003 | 06:00 PM
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From: Manassas, VA
Car: 89 Formula Firebird
Engine: 305 - Demon 525
Transmission: 700R4
so what do I measure them in? Decimal or what?
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Old Jan 10, 2003 | 06:16 PM
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From: Loveland, OH, US
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Measure what?

What are they? beside hogging out the intake flange, what's been done to them? What kind of valves are in them? What do the exhaust ports look like? What's the chamber volume? .....
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Old Jan 10, 2003 | 06:24 PM
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From: Manassas, VA
Car: 89 Formula Firebird
Engine: 305 - Demon 525
Transmission: 700R4
thats the stuff I'm trying to find out
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Old Jan 10, 2003 | 06:32 PM
  #7  
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From: Manassas, VA
Car: 89 Formula Firebird
Engine: 305 - Demon 525
Transmission: 700R4
that port measured out to 1" 5/16 how do you convert that to what your saying?
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Old Jan 10, 2003 | 06:50 PM
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Hmmm...

You need more precision; measurements need to be in decimal units, out to at least 2 places beyond the decimal point.

You need a set of cailpers.

The actual measurements of the intake port at the flange aren't worth much as far as identification. Somebody has hogged them out hugely. It might be worthwhile to identify what intake gasket would fit without hanging into the ports though.

Measure the valve spring diameter, intake and exhaust valve diameter, read off any casting marks... the rocker studs aren't in all the way, looks like they're set up for guide plates but they're not there..... lots of stuff to explore.

Pop some valves out and show us some ports viewed from the cylinder side, and the valves themselves.
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Old Jan 10, 2003 | 07:19 PM
  #9  
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From: Manassas, VA
Car: 89 Formula Firebird
Engine: 305 - Demon 525
Transmission: 700R4
http://www.darkenedwolf.com/pix/head1.JPG
http://www.darkenedwolf.com/pix/head2.JPG
http://www.darkenedwolf.com/pix/head3.JPG


castings say

340292 GM 49


Valve springs measure 1" 1/2
Intake valve= 2" 1/16
exhaust valve= 1" 9/16


so what does that tell ya?

Last edited by redbird_400; Jan 10, 2003 at 10:45 PM.
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Old Jan 10, 2003 | 07:20 PM
  #10  
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From: Manassas, VA
Car: 89 Formula Firebird
Engine: 305 - Demon 525
Transmission: 700R4
BTW that rust will scratch off with a finger nail. There doesnt seem to be any damage to the metal. How can I clean that properly?

can someone help me out here? I have no clue what I'm looking for on these heads. I bought them from some dude. They have been passed around from 4 of my freinds who know a krapload more then me. They have only been used once with this setup. This dude on the drag track had them in his Chevy pickup. He pulled a wheelie and broke a 4 speed muncie is what I hear. They are set up for some serious power I assume.

Last edited by redbird_400; Jan 10, 2003 at 07:26 PM.
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Old Jan 10, 2003 | 07:48 PM
  #11  
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From: N.C. coast
Car: '84 Z28
Engine: Goodwrench 350
Transmission: 700R4
Axle/Gears: good guess
you mean 340292. Those heads are the freakin' deal. They were over the counter performance heads in the 70's. They were badass without any port work done.
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Old Jan 10, 2003 | 10:45 PM
  #12  
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From: Manassas, VA
Car: 89 Formula Firebird
Engine: 305 - Demon 525
Transmission: 700R4
Oh yeah! that is a 3 your right! let me change it
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Old Jan 10, 2003 | 11:00 PM
  #13  
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From: Manassas, VA
Car: 89 Formula Firebird
Engine: 305 - Demon 525
Transmission: 700R4
I found this web site

Maybe these are better then I though


http://www.geocities.com/allchevelles/index-74.html


340292 73-80 2.02/1.60 300HP & up 64cc Chambers. High performance heads. hard to find. angle plugs.



and I found this..... looks like you were right when you said over the counter. It says here they were known as the Turbo heads


http://www.chevytalk.com/tech/engine/SBC_Heads.html

"292" – 3917292, or 340292. Both are good performance heads. The 3917292 was found on 1968 327 and 350 engines, had 1.94/1.50" valves, 64CC combustion chambers, straight plug configuration, not sure on the accessory holes, and I do not have any port volume data on these heads. These heads have double hump casting marks. The 340292 was available from GM "over the counter". This version had angle plug configuration, 2.02/1.60" valves, 64CC combustion chambers. These were known as the "Turbo" heads.

Last edited by redbird_400; Jan 10, 2003 at 11:05 PM.
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Old Jan 11, 2003 | 08:53 AM
  #14  
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Nice, big springs, ports, and valves. If you can get the chamber volume to work in your combination for compression (domed pistons maybe?) you might have something there. With those chambers and an 0.031" head gasket, you should net 9.97:1 static compression on a stock 350 with flat-tops.

If you tell him you're only running a 350, and that's all you can spend ($350), do you think they might be a go?

If you can't use them, send them my way...

EDIT: It looks like someone might have had a clue about what they were doing with these heads - it appears that they are painted with G.E. Glyptal enamel inside.

Last edited by Vader; Jan 11, 2003 at 08:55 AM.
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Old Jan 11, 2003 | 10:35 AM
  #15  
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From: Manassas, VA
Car: 89 Formula Firebird
Engine: 305 - Demon 525
Transmission: 700R4
Yeah the story is that someone had but about $1200.00 into these heads. They have been passed around from the original user to 3 other of my friends that could not use them. It would cost me more $ then I can think of to build an engine to hadle these.
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Old Jan 11, 2003 | 02:41 PM
  #16  
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From: Ontario, Canada
Car: 1988 Firebird S/E
Engine: 406Ci Vortec SBC
Transmission: TH-350/3500stall
Axle/Gears: 7.5" Auburn 4.10 Posi-Traction
Those heads have real good potential.
It appears from your pics that they have been drilled for
400sbc steam holes. they also appear to have been shaved.

Chamber cc will be less than 64cc.

Best to dissassemble them and go through them
to check 'em out before ya bolt 'em on.

I'd cc the chambers so you can get your compression ratio right for what ever motor your going to build.
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Old Jan 11, 2003 | 04:10 PM
  #17  
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Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Also need guide plates in order to use them, and they aren't there (note gap between stud shoulder and mounting boss).

When I had a set of those heads (mid-'70's, unported), they were called "LT1" heads.
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Old Jan 12, 2003 | 09:59 AM
  #18  
redbird_400's Avatar
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From: Manassas, VA
Car: 89 Formula Firebird
Engine: 305 - Demon 525
Transmission: 700R4
Well I think I'm going to sell them. I have had these for over a year without using them. So where is the best place to take them to get them cleaned up and to get some test done to them. I want some paper work for them that I can give to the new owner. Magniflex and stuff like that. Are there any other test? Like spring compression or something?
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