LT1 intake manifold question
06-01-2011, 05:21 PM
#16
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Re: LT1 intake manifold question
Air foil dyno test on an LT1. 2.4HP/2.1ft-lb. Sorry, it is absolutely impossible to feel that seat-of-the-pants.
http://www.ws6.com/mod-4.htm
You remember incorrectly. Red part is correct 
. The LT4 heads have taller intake ports. The LT4 intake manifold does not. It has more metal at the top of the port to allow the ports on the intake to be ported to match the LT4 heads, but GM never finished up the project. As a result, the LT4 intake manifold ports/runners are virtually identical to the LT1 intake, and offer no advantage at all, unless you have LT4 heads, and want to invest in porting the LT4 intake.
Both the LT1 and LT4 intakes have 52mm throttle bores. The point at which you need a 58mm throttle body is in excess of 500HP. The shop that built my engine was able to show me, using air flow measurement on the engine dyno, that my 58mm TB was not needed, and infact was able to supply the air required for 500HP at only 77% open.... equivalent area to a 52mm TB.
And finally, you can't bolt an LT4 intake on LT1 heads without machine work. The taller metal on the runners interferes with the LT1 head valve cover rail. Either the valve cover rail on the heads needs to be machined, or the metal at the top of the intake runners needs to be machined.
http://www.ws6.com/mod-4.htm
The LT4 manifold was powdercoated red and had larger openings to the heads. (If I remember correctly).
. The LT4 heads have taller intake ports. The LT4 intake manifold does not. It has more metal at the top of the port to allow the ports on the intake to be ported to match the LT4 heads, but GM never finished up the project. As a result, the LT4 intake manifold ports/runners are virtually identical to the LT1 intake, and offer no advantage at all, unless you have LT4 heads, and want to invest in porting the LT4 intake.Both the LT1 and LT4 intakes have 52mm throttle bores. The point at which you need a 58mm throttle body is in excess of 500HP. The shop that built my engine was able to show me, using air flow measurement on the engine dyno, that my 58mm TB was not needed, and infact was able to supply the air required for 500HP at only 77% open.... equivalent area to a 52mm TB.
And finally, you can't bolt an LT4 intake on LT1 heads without machine work. The taller metal on the runners interferes with the LT1 head valve cover rail. Either the valve cover rail on the heads needs to be machined, or the metal at the top of the intake runners needs to be machined.
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