LT4 intake manifold gasket question
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Burning Brakes
Joined: Feb 2002
Posts: 871
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From: Union KY
LT4 intake manifold gasket question
I've heard that the stock LT4 GM intake manifold gasked significantly obstructs the opening between the intake and head ports. I'm told that aftermarket gaskets are available that eliminate that condition. Has anyone had direct experience with this alteration and did it make a noticible difference in performance / horsepower?
Cire96
Cire96
Le Mans Master
Joined: Jul 1999
Posts: 8,683
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From: Phoenix AZ
Re: LT4 intake manifold gasket question (cire96)
GM makes a performance intake gasket for the LT4, the last four digits of the part number are 7777. Gasket matching can certainly help make some more power, but you will most likely not notice it especially if you are using stock heads and cam. But it is true that little things do add up in the end.
Race Director
Joined: Nov 1999
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From: Michigan in the summer, Florida the rest of the time
St. Jude Donor '08-'09-'11
Re: LT4 intake manifold gasket question (cire96)
Jim Mason may pop in. :) Here's an excerpt from his LT4 Intake Porting Tech Tip at http://www.hashmarks.com/techtips/in...ke_porting.htm:
Brad
[Modified by GS Ragtop, 11:30 PM 3/28/2003]
Reassembly is the reverse of the above using new gaskets. For gaskets there are two alternatives. Use the production gasket (p/n 12528884) which blocks the ports and would require modification or use the LT4 gasket from the GM Performance Parts catalog (p/n 12367777) which does not block the ports. I choose the "77" gaskets for ease of assembly. I purchased them via Worldparts.com from Hutton Chevrolet in Memphis, TN for ~$16 each ("77" gaskets are sold in quantities of one for some strange reason). Shipping was free, and I had them the next day.
[Modified by GS Ragtop, 11:30 PM 3/28/2003]
