Factory exhaust size 1988 Firebird formula
#1
Member
Thread Starter
iTrader: (4)
Join Date: Jul 2003
Location: Trinity, AL
Posts: 108
Likes: 0
Received 1 Like
on
1 Post
Car: 1987 trans am, 1988 Formula
Engine: 305 LG4, 305 LB9 TPI
Transmission: 700R4 in both
Factory exhaust size 1988 Firebird formula
I have a 1988 Firebird Formula with the LB9 305 TPI. I need to know what the stock exhaust pipe size would have been on this engine. The cat has been removed long before I had it and will stay removed. If anybody has the GM parts manual or the diagram showing the exhaust sizes and layout, that would be helpful as well. I'm trying to put this car back stock as possible w/o the cat because it would be stopped up anyway, and make a good driving car out of it. Any help is appreciated.
#2
Member
Join Date: Feb 2016
Location: Kingston, ON
Posts: 174
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1985 Trans Am
Engine: 350
Transmission: T5
Re: Factory exhaust size 1988 Firebird formula
Stock it could have been 2.25" or 2.5". Rock Auto sells exhaust pipes in OEM sizes that are reasonably priced.
#3
Supreme Member
iTrader: (2)
Join Date: Mar 2014
Location: South Ms
Posts: 4,477
Received 753 Likes
on
516 Posts
Car: 89 Firebird
Engine: 355 TBI
Transmission: 700R4
Axle/Gears: 10 Bolt.Posi-3.73s
Re: Factory exhaust size 1988 Firebird formula
The LB9 would have had 2.5 im pretty sure. The L03 had the choking 2.25. Do yourself a favor and go ahead 3in all the way you wont be sorry. With the way these cars are setup with one exhaust pipe it helps to go a lil bigger especially if you upgrade with a bigger stronger engine down the road.
#4
Member
Thread Starter
iTrader: (4)
Join Date: Jul 2003
Location: Trinity, AL
Posts: 108
Likes: 0
Received 1 Like
on
1 Post
Car: 1987 trans am, 1988 Formula
Engine: 305 LG4, 305 LB9 TPI
Transmission: 700R4 in both
Re: Factory exhaust size 1988 Firebird formula
Is there a bolt on kit that does not have a provision for a catalytic converter? Most bolt on systems I've found have the flange at the front of the pipe for it and I'm not going to put one back on. I guess if that were the case Id have to cut the flange off and put in a piece of pipe for that part.
Thread
Thread Starter
Forum
Replies
Last Post
Randomtask2
Tech / General Engine
6
03-17-2016 11:23 PM
bad camaro RS
Aftermarket Product Review
2
12-26-2000 10:07 AM