LT1 Intake Manifold
07-10-2006, 03:01 PM
#1
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LT1 Intake Manifold I have a 95 Trans Am and some how my Intake manifold has a hole in it which is causing a crazy vacumn leak. I have no idea how it happened but anyways I need a new manifold.
I read that the 93 Manifolds wont work cause the fuel rails are different? Is this true? So will any other 94-97 LT1 Intake fit? Were they different for the vettes and such?
Thanks
I read that the 93 Manifolds wont work cause the fuel rails are different? Is this true? So will any other 94-97 LT1 Intake fit? Were they different for the vettes and such?
Thanks
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07-10-2006, 08:26 PM
#8
There are about 5 different LT1/L99 intakes all interchangable and will function just fine, minor variances in port shape the later ones not being true rectangles, the early ones being rectangles actually larger than the head ports which would be worse for flow than a smaller port that lines up well.
People get all scared of L99 stuff but it will work and will likely cost you less even though it could be the same casting. That is the 4.3L base motor in the 94-96 Caprice it is a smaller bore, destroked LT1, a b-body LT1 intake would work perfectly too and again likely be cheaper than f-body sourced parts and the same exact casting. At a boneyard you pay a premium for parts off a "performance" car, when you find the same exact part on a "grandpa" car the part is less desirable to the ignorant masses and you can get it cheaper.
People get all scared of L99 stuff but it will work and will likely cost you less even though it could be the same casting. That is the 4.3L base motor in the 94-96 Caprice it is a smaller bore, destroked LT1, a b-body LT1 intake would work perfectly too and again likely be cheaper than f-body sourced parts and the same exact casting. At a boneyard you pay a premium for parts off a "performance" car, when you find the same exact part on a "grandpa" car the part is less desirable to the ignorant masses and you can get it cheaper.
07-10-2006, 10:15 PM
#10
1993 - 10208145 - No fuel cross over.
1994-96 - 10108471, 10108629F, 10108630 - The 10108630 seems to be the most common. I have a bunch of them. They came on the LT1's (both aluminum and iron heads) and the L99's. I have never seen the 10108471 or 10108629F. Anybody have one of them?
1997 - 12552138 - Ports are the same size and shape as the LT4 intake. You will still have to weld on them to port match them to aftermarket heads like any other LT1 intake.
I have run a best of 10.50 N/A with an untouched 10208145! That was when the NHRA allowed them on all years. Now they are a 1993 only item.
Does anyone have a 12552138 that they would like to sell? I need a couple for my Stock Eliminator motors. Must be untouched castings.
Thanks,
Daren
1994-96 - 10108471, 10108629F, 10108630 - The 10108630 seems to be the most common. I have a bunch of them. They came on the LT1's (both aluminum and iron heads) and the L99's. I have never seen the 10108471 or 10108629F. Anybody have one of them?
1997 - 12552138 - Ports are the same size and shape as the LT4 intake. You will still have to weld on them to port match them to aftermarket heads like any other LT1 intake.
I have run a best of 10.50 N/A with an untouched 10208145! That was when the NHRA allowed them on all years. Now they are a 1993 only item.
Does anyone have a 12552138 that they would like to sell? I need a couple for my Stock Eliminator motors. Must be untouched castings.
Thanks,
Daren
07-11-2006, 02:22 AM
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Well the mechanic told me there was a hole in my manifold...
I just pulled the manifold off and it looks ok but the RTV seal wasnt too great so im thinking thats what it is?
I just pulled the manifold off and it looks ok but the RTV seal wasnt too great so im thinking thats what it is?
07-11-2006, 11:55 AM
#13
Originally Posted by Honda Hunter
Then why do L98 guys do LT1 intake conversions?
Can I guess you read my response too fast and do not understand what an L99 is????? The L98 is TPI, the L99 is a smaller displacement version of the LT1.
07-11-2006, 03:22 PM
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Originally Posted by CK9887
Well the mechanic told me there was a hole in my manifold...
I just pulled the manifold off and it looks ok but the RTV seal wasnt too great so im thinking thats what it is?
I just pulled the manifold off and it looks ok but the RTV seal wasnt too great so im thinking thats what it is?
The RTV is only there to seal the oil coming from the lifter valley area, there's not any rtv sealing your intake plenum or ports from atmosphere...
You probably have a vacuum leak from some buried vacuum line somewhere that got disconnected. Or even the vacuum line going to the EGR valve. Or a faulty EGR valve or gasket.
Look that manifold over really well, if theres a hole you should see it and not have any problems getting it welded shut.
Do yourself a favor and go buy a haynes manual and start fixing things yourself. Instead of being one of the 'ignorant masses' who pay people to pretend to fix their cars.
07-11-2006, 04:14 PM
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Well the manifold is completly off of my car and it looks ok... I went and bought new gaskets for when I put it back on... Im just hoping somehow this fixes the problem. Maybe when I reinstall everything I will hook up a vacumn line that was undone or something... I dont know i just hope pulling this manifold off wasnt a waste of time.
