89 Firebird with 99 Vortec 5.7, manifolds don't fit!
10-25-2016, 07:32 AM
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89 Firebird with 99 Vortec 5.7, manifolds don't fit!
Trying to finish up swapping a 5.7 vortec engine (from a 99 van) into an 89 firebird. I have used the TPI/vortec baseplate conversion which worked great. Almost ready to drop the engine into the car, when I can not bolt up the drivers side exhaust manifold. The factory 5.7 TPI heads have a second bolt pattern for the manifold, due to the rear port on the factory manifolds. The Vortec heads do not have this extra wide hole, therefore the factory manifolds can not bolt up.
Customer would like to retain the AIR injection system and has previously had a new Y pipe and cat back built for the factory manifolds.
So my question... is there a direct replacement header or manifold that retains the AIR system and will bolt up to the Vortec cylinder heads?
Thanks.
Customer would like to retain the AIR injection system and has previously had a new Y pipe and cat back built for the factory manifolds.
So my question... is there a direct replacement header or manifold that retains the AIR system and will bolt up to the Vortec cylinder heads?
Thanks.
10-31-2016, 02:09 PM
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Car: 1988 Gta trans am project 1-1/2
Engine: 86 4 bolt main cammed sbc 355 hsr
Transmission: 89 wc bw t5
Axle/Gears: Bw 9 bolt (3.27) pbr 11in
Re: 89 Firebird with 99 Vortec 5.7, manifolds don't fit!
Trying to finish up swapping a 5.7 vortec engine (from a 99 van) into an 89 firebird. I have used the TPI/vortec baseplate conversion which worked great. Almost ready to drop the engine into the car, when I can not bolt up the drivers side exhaust manifold. The factory 5.7 TPI heads have a second bolt pattern for the manifold, due to the rear port on the factory manifolds. The Vortec heads do not have this extra wide hole, therefore the factory manifolds can not bolt up.
Customer would like to retain the AIR injection system and has previously had a new Y pipe and cat back built for the factory manifolds.
So my question... is there a direct replacement header or manifold that retains the AIR system and will bolt up to the Vortec cylinder heads?
Thanks.
Customer would like to retain the AIR injection system and has previously had a new Y pipe and cat back built for the factory manifolds.
So my question... is there a direct replacement header or manifold that retains the AIR system and will bolt up to the Vortec cylinder heads?
Thanks.
11-01-2016, 11:15 AM
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Re: 89 Firebird with 99 Vortec 5.7, manifolds don't fit!
Either way, I installed a set of hooker 2055's with the air tubes.
11-01-2016, 12:09 PM
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Car: 89 Firebird
Engine: 355 TBI
Transmission: 700R4
Axle/Gears: 10 Bolt.Posi-3.73s
Re: 89 Firebird with 99 Vortec 5.7, manifolds don't fit!
I ran into that problem with Vortec heads years ago and the extra bolthole with the TPI manifolds so i ran headers also.
11-01-2016, 02:32 PM
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Car: 1987 SC/1985 TA
Engine: 350/vortec/fitech
Transmission: T56
Axle/Gears: 3.27 9-bolt
Re: 89 Firebird with 99 Vortec 5.7, manifolds don't fit!
in case someone else stumbles upon this, many have installed the factory exhaust manifolds without the rear most bolt with no leaks, myself included.
The right side was the issue though. The location of the down pipe on that one is where the normal bolt hole is. The left side allows all the bolts to be used.
The right side was the issue though. The location of the down pipe on that one is where the normal bolt hole is. The left side allows all the bolts to be used.
01-03-2017, 01:52 PM
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Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: 89 Firebird with 99 Vortec 5.7, manifolds don't fit!
Not all Vortec heads lack the 7th bolt hole. Also LT1 manifolds have enough meat on the flange to drill a hole for the Vortec pattern. Would require slightly revising the exhaust and using the LT1 exhaust flanges but the LT1 manifolds flow much better and match the Vortec exhaust ports better. The manifolds also have AIR injection provisions.
