Yet another intake gasket question
Thread Starter
Instructor
Joined: May 2011
Posts: 103
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From: Lithia FL
Yet another intake gasket question
Guys: I have searched for threads and found a number of them that seem to help. However, I need definitive advice. I have a 1986 with aluminum heads. I am going in for new injectors and may have the intake ported while in that far. Without knowing what gaskets are in there now, I am concerned about what gaskets to get with regard to the water passages. Some kits show all of them wide open. Some show rear passages nearly blocked except for a small hole. I have also seen some sets with the middle passageways necked down a bit with a large circular hole. From what I can tell, blocking the rear passages with the small holes was done to reduce head gasket failure and is OK to use. Are there any reasons you would not go with one where all passages are open? If so, what is the reasoning? Seems like cutting down the flow rate in rear would be part of why these run hot? Please chime in. Thanks!
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Go here and read about all the differences: http://www.hotrodlane.cc/PDFFILES/TPIStory.pdf
Essentially, the Vette TPI keeps the flow at the back of the Heads longer to increase cooling and with the restrictors in the gaskets, it needs/gets additional coolant from the Core. F body doesn't use this so if you eliminate the gasket restrictors you can eliminate the supply hose.
Essentially, the Vette TPI keeps the flow at the back of the Heads longer to increase cooling and with the restrictors in the gaskets, it needs/gets additional coolant from the Core. F body doesn't use this so if you eliminate the gasket restrictors you can eliminate the supply hose.
Le Mans Master
Joined: Feb 2005
Posts: 6,479
Likes: 565
From: Clearwater Florida
...... The rear of the Tuned Port Manifold is not cast with a crossover water passage ... the only needed water source is for the heater hose by-pass fitting on the pass side rear corner ... thus the small diameter hole in the gskt ......... same for the center hole ... its for an exhaust crossover that is blocked on the TPI manifold ... the EGR valve is fed exhaust gas thru the pipe off the rear corner of the ex manifold .........
Last edited by C409; May 15, 2012 at 02:54 PM.
