gasket matched ports
11-28-2013, 08:56 PM
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gasket matched ports Hey, I'm new here and was wondering if the computer will be able to compensate for gasket matched ports in a stock 95 lt1? The motor came out of a 9c1 caprice. Thnks
11-29-2013, 06:38 AM
#2
bunch of things wrong here. First are you talking intake or exhaust ports?
Second sounds kind of like it is maybe a retrofit?
If a retrofit and you think you can just wire in the pcm and do zero reprogramming consider abandoning the project right now. If this is just an engine swap on an already LT1 equipped car again don't screw with the ports if you aren't willing to address the pcm. It will run fine but if you are unwilling to deal with the pcm don't bother trying simple mods either. If an L99 car receiving an LT1 then you are at the very least likely to have speedo issues without reprogramming the pcm.
Far as actually gasket matching, the exhaust ports on the heads SHOULD be smaller than the exhaust manifolds or headers to combat reversion.
On the intake side opening up the gasket surface to gasket size makes for a fat spot in the middle of the combined manifold and head port which just makes it harder for the air to flow the air having to expand to fill the fatter area and then speed back up to get down the rest of the port is counterproductive. On mild engines with unported heads the later intakes with the smaller trapezoidal ports are actually slightly better than the early larger rectangular ports because they align better.
Second sounds kind of like it is maybe a retrofit?
If a retrofit and you think you can just wire in the pcm and do zero reprogramming consider abandoning the project right now. If this is just an engine swap on an already LT1 equipped car again don't screw with the ports if you aren't willing to address the pcm. It will run fine but if you are unwilling to deal with the pcm don't bother trying simple mods either. If an L99 car receiving an LT1 then you are at the very least likely to have speedo issues without reprogramming the pcm.
Far as actually gasket matching, the exhaust ports on the heads SHOULD be smaller than the exhaust manifolds or headers to combat reversion.
On the intake side opening up the gasket surface to gasket size makes for a fat spot in the middle of the combined manifold and head port which just makes it harder for the air to flow the air having to expand to fill the fatter area and then speed back up to get down the rest of the port is counterproductive. On mild engines with unported heads the later intakes with the smaller trapezoidal ports are actually slightly better than the early larger rectangular ports because they align better.
11-29-2013, 12:48 PM
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I gotcha on the pressure drop and yes its a retrofit that I did some 8 years ago, I used all the stuff from the Caprice. Im gonna do the rear dist gig and was gonna be in it anyway. Is there an intake gasket that fits the ports better? thanks