manifolds and performance
Senior Member


Joined: Apr 2016
Posts: 733
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Car: 1991 base firebird
Engine: tbi 305
Transmission: 700r4
Re: manifolds and performance
m not 100% on CARB certification but I feel like one of the big manufactures has to be California legal. if you have no choice but to keep the manifolds and exhaust. I would start with the cat. the factory cat is a horse power death trap. replace it with a high flow cat. there are a lot to choose from now days. I would also do more research on a carb legal exhaust system. there has to be one right?
Re: manifolds and performance
But , I'd still consider moving , earthquakes & all .....
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Joined: Feb 2017
Posts: 4,185
Likes: 576
From: Meriden, CT 06451
Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: manifolds and performance
Are you allowed to change the "T" pipe to a real "Y" pipe? That is a HUGE restriction.
Edit: never mind - not an f-body.
Edit: never mind - not an f-body.
Supreme Member




Joined: Jan 2009
Posts: 2,316
Likes: 116
From: belle fourche,s.d.
Car: '82 z28
Engine: L83 5.7
Transmission: 700r4-1985
Axle/Gears: 3.42 posi
Re: manifolds and performance
IIRC,those trucks had better flowing iron manifolds than our thirds were saddled with-make up a better "y",high flow cat,larger pipe diameter better muffler-just make it look stock,doubt anyone at the smog station is going to be too picky about a 1985 pickup as long as all the smog parts appear to be there
Joined: Jan 2005
Posts: 10,450
Likes: 508
From: Hurst, Texas
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: manifolds and performance
An 85 truck had the same design log manifolds as a 3rd gen. Different flange and exit angle though.
That being said most of the 73-87 trucks had the manifolds that drop down under the spark plugs. Get a set of manifolds for an early 90s 350 van. They will look stock, have smog provisions and have a 2.25" exit.
That being said most of the 73-87 trucks had the manifolds that drop down under the spark plugs. Get a set of manifolds for an early 90s 350 van. They will look stock, have smog provisions and have a 2.25" exit.
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jcurrieirocz
Tech / General Engine
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Nov 26, 2003 06:52 PM





Either buy a factory built CARB certified performance vehicle , , , , Or move to a more performance modification friendly State .....
