Author Topic: 302 question for JM  (Read 4100 times)

GaryL

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302 question for JM
« on: February 20, 2010, 05:11:09 PM »
Year ago you recommended the GM .028" head gaskets to me. There is alway a lot of discussion about quench on hipo engines. With an undecked block and a .028" gasket the quench ends up a little higher than what is generally recommended. How do you build a 302 and what do you consider the proper quench for stock rebuilds? Thanks.
Gary

Lemans Blue X33. DZ, M20, manual steering. Only BU code rear end is original.

fireZ

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Re: 302 question for JM
« Reply #1 on: February 20, 2010, 07:18:44 PM »
I use a 0.040 head gasket on my engines that have not been decked. It lowers compression a little but street-able on pump gas.
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Jerry@CHP

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Re: 302 question for JM
« Reply #2 on: February 21, 2010, 11:33:39 PM »
We usually use the 711 or the composition GM gasket that's about .030" compressed.  Depends on where the piston is at TDC.

Jerry

69Z28

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Re: 302 question for JM
« Reply #3 on: February 22, 2010, 01:04:21 AM »
We usually use the 711 or the composition GM gasket that's about .030" compressed.  Depends on where the piston is at TDC.

Jerry

Hello. I was asking about what gasket to use on the T.C. site. I have a .030 over bore stock rebuilt DZ engine, balanced. The pistons are .021 below the deck and block surface has not been decked. Just a little confused from the answers provide due to the quench specs. What would be recommended in this application?

Thanks, Gary
GaryC

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GaryL

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Re: 302 question for JM
« Reply #4 on: February 22, 2010, 04:10:25 AM »
It sounds like quench is not that important in a 30-30 cammed 302 for some reason.
Gary

Lemans Blue X33. DZ, M20, manual steering. Only BU code rear end is original.

Jerry@CHP

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Re: 302 question for JM
« Reply #5 on: February 22, 2010, 09:07:45 PM »
I would use the 711 gasket.  When you get into this quench topics then it becomes more of a Stock Eliminator get every last HP issue rather than a good running 302 for the street.  Don't worry about what everyone thinks, I've been in this hobby long enough to know that you will get 100 different answers from 100 different people.  We get about 360-380 out of a stock rebuild on a pedigree 302 on pump gas.  We can step it up from that if requested. 

Jerry

69Z28

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Re: 302 question for JM
« Reply #6 on: February 23, 2010, 02:38:09 AM »
I would use the 711 gasket.  When you get into this quench topics then it becomes more of a Stock Eliminator get every last HP issue rather than a good running 302 for the street.  Don't worry about what everyone thinks, I've been in this hobby long enough to know that you will get 100 different answers from 100 different people.  We get about 360-380 out of a stock rebuild on a pedigree 302 on pump gas.  We can step it up from that if requested. 

Jerry


Thanks for the info. Where can I get this 711 gasket?
GaryC

'UNRESTORED' 1969 Cortez Silver X33D80 Z28

Gramps69Z

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Re: 302 question for JM
« Reply #7 on: February 23, 2010, 03:09:14 AM »
GM part #3830711, check with your dealer. Compressed thickness is .026".

Google the part number and see what happens.
Captain John Wykoff
Destin Fire     5 months  to go

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I'm a COWBOYS fan.

69Z28

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Re: 302 question for JM
« Reply #8 on: February 23, 2010, 04:15:49 AM »
Thanks
GaryC

'UNRESTORED' 1969 Cortez Silver X33D80 Z28

Jerry@CHP

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Re: 302 question for JM
« Reply #9 on: February 23, 2010, 08:28:02 PM »
John,

They usually compress to .020" when we check them on tear down.  I suspect that they can vari.  This is what I have on my current 302 in the race car.

http://www.youtube.com/watch?v=L-2GZtY9REY

Jerry

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Re: 302 question for JM
« Reply #10 on: February 23, 2010, 09:58:59 PM »
The 3830711 is currently on backorder from GM. I do have a set in stock if you cannot locate them locally.
GM parts-tech. Polar Chevrolet White Bear Lake, Mn

Gramps69Z

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Re: 302 question for JM
« Reply #11 on: February 24, 2010, 12:57:29 AM »
Jerry, I was going with what GM stated on their web site. 

http://www.gmpartsdirect.com/performance_parts/store/catalog/Product.jhtmlPRODID=701&CATID=697.html

FYI, the 902 DZ carburetor is working great. It's amazing how you can take a 40 year old part and make it new again.
Thanks again for the professional service.
Captain John Wykoff
Destin Fire     5 months  to go

I'm sick and tired of mismanagement and disappointment. 
I'm a COWBOYS fan.

Jerry@CHP

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Re: 302 question for JM
« Reply #12 on: February 24, 2010, 02:06:36 AM »
Thanks John!

I hope that these gaskets are not being discontinued.  The back order issue is not a good sign.

Jerry

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Re: 302 question for JM
« Reply #13 on: February 24, 2010, 02:39:25 AM »
That part # 3830711 does come up as discontinued from what I have found.  >:(

GaryL

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Re: 302 question for JM
« Reply #14 on: February 24, 2010, 09:10:36 PM »
Jerry, you recommended the #10105117 to me 4 years ago. Have you changed or possibly the "117" was transposed to "711"? Thanks. No matter the composition "117 works great so far.
Gary

Lemans Blue X33. DZ, M20, manual steering. Only BU code rear end is original.

Jerry@CHP

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Re: 302 question for JM
« Reply #15 on: February 24, 2010, 10:20:28 PM »
Don't think I did.  The 711 will make a little more compression and HP.  .010" difference in thickness.  I called my source today and he told me that GM is having another vendor make the 3830711 gaskets, will know more on March 10th.  They should still be available........keep your fingers corssed.

Jerry